Add Docker images for supported architectures

[lucacome]

The base Docker image for NGINX is published for a variety of linux architectures. Would it make sense to match them as close as possible?

I'm not very familiar with CircleCI and couldn't figure out if it comes with Docker Buildx already installed (and I don't have a way to test it), but if it does it's just a simple as simple as

docker buildx build --push --platform linux/arm64,linux/amd64,linux/ppc64le -t opentracing-contrib/nginx-opentracing:latest .

I was able to build for arm64 and ppc64le on a linux machine (other than amd64).

The build for linux/s390x failed because of boringssl not supporting it

#27 347.7 [C]       Compiling src/boringssl/err_data.c
#27 348.1 In file included from src/boringssl/err_data.c:17:0:
#27 348.1 third_party/boringssl/include/openssl/base.h:122:2: error: #error "Unknown target CPU"
#27 348.1  #error "Unknown target CPU"
#27 348.1   ^~~~~

The build for linux/arm failed with

#10 6446.7 [ 87%] Performing install step for 'Boost'
#10 6446.8 Unable to load Boost.Build: could not find "boost-build.jam"

[lucacome]

This is the full error for linux/arm if it helps

#10 6446.7 [ 87%] Performing install step for 'Boost'
#10 6446.8 Unable to load Boost.Build: could not find "boost-build.jam"
#10 6446.8 ---------------------------------------------------------------
#10 6446.8 BOOST_ROOT must be set, either in the environment, or
#10 6446.8 on the command-line with -sBOOST_ROOT=..., to the root
#10 6446.8 of the boost installation.
#10 6446.8
#10 6446.8 Attempted search from /root/.hunter/_Base/d45d77d/05154f7/3b7ee27/Build/Boost/Source up to the root
#10 6446.8 at /root/.hunter/_Base/d45d77d/05154f7/3b7ee27/Build/Boost/share/boost-build
#10 6446.8 and in these directories from BOOST_BUILD_PATH and BOOST_ROOT: /usr/share/boost-build, /root/.hunter/_Base/d45d77d/05154f7/3b7ee27/Install.
#10 6446.8 Please consult the documentation at 'http://www.boost.org'.
#10 6446.8 make[5]: *** [CMakeFiles/Boost.dir/build.make:74: Boost-prefix/src/Boost-stamp/Boost-install] Error 1
#10 6446.8 make[5]: Leaving directory '/root/.hunter/_Base/d45d77d/05154f7/3b7ee27/Build/Boost/Build'
#10 6446.8 make[4]: *** [CMakeFiles/Makefile2:73: CMakeFiles/Boost.dir/all] Error 2
#10 6446.8 make[4]: Leaving directory '/root/.hunter/_Base/d45d77d/05154f7/3b7ee27/Build/Boost/Build'
#10 6446.8 make[3]: *** [Makefile:84: all] Error 2
#10 6446.8 make[3]: Leaving directory '/root/.hunter/_Base/d45d77d/05154f7/3b7ee27/Build/Boost/Build'
#10 6446.9
#10 6446.9 [hunter ** FATAL ERROR **] Build step failed (dir: /root/.hunter/_Base/d45d77d/05154f7/3b7ee27/Build/Boost
#10 6446.9 [hunter ** FATAL ERROR **] [Directory:/root/.hunter/_Base/Download/Hunter/0.23.249/d45d77d/Unpacked/cmake/projects/Boost]
#10 6446.9
#10 6446.9 ------------------------------ ERROR -----------------------------
#10 6446.9     https://hunter.readthedocs.io/en/latest/reference/errors/error.external.build.failed.html
#10 6446.9 ------------------------------------------------------------------
#10 6446.9
#10 6446.9 CMake Error at /root/.hunter/_Base/Download/Hunter/0.23.249/d45d77d/Unpacked/cmake/modules/hunter_error_page.cmake:12 (message):
#10 6446.9 Call Stack (most recent call first):
#10 6446.9   /root/.hunter/_Base/Download/Hunter/0.23.249/d45d77d/Unpacked/cmake/modules/hunter_fatal_error.cmake:20 (hunter_error_page)
#10 6446.9   /root/.hunter/_Base/Download/Hunter/0.23.249/d45d77d/Unpacked/cmake/modules/hunter_download.cmake:623 (hunter_fatal_error)
#10 6446.9   /root/.hunter/_Base/Download/Hunter/0.23.249/d45d77d/Unpacked/cmake/projects/Boost/hunter.cmake:425 (hunter_download)
#10 6446.9   /root/.hunter/_Base/Download/Hunter/0.23.249/d45d77d/Unpacked/cmake/modules/hunter_add_package.cmake:62 (include)
#10 6446.9   build/cmake/DefineOptions.cmake:110 (hunter_add_package)
#10 6446.9   CMakeLists.txt:58 (include)
#10 6446.9
#10 6446.9
#10 6446.9 -- Configuring incomplete, errors occurred!
#10 6446.9 See also "/root/.hunter/_Base/d45d77d/05154f7/3b7ee27/Build/thrift/Build/thrift-Release-prefix/src/thrift-Release-build/CMakeFiles/CMakeOutput.log".
#10 6446.9 make[2]: *** [CMakeFiles/thrift-Release.dir/build.make:110: thrift-Release-prefix/src/thrift-Release-stamp/thrift-Release-configure] Error 1
#10 6446.9 make[1]: *** [CMakeFiles/Makefile2:73: CMakeFiles/thrift-Release.dir/all] Error 2
#10 6447.0 make: *** [Makefile:84: all] Error 2
#10 6447.0
#10 6447.0 [hunter ** FATAL ERROR **] Build step failed (dir: /root/.hunter/_Base/d45d77d/05154f7/3b7ee27/Build/thrift
#10 6447.0 [hunter ** FATAL ERROR **] [Directory:/root/.hunter/_Base/Download/Hunter/0.23.249/d45d77d/Unpacked/cmake/projects/thrift]
#10 6447.0
#10 6447.0 ------------------------------ ERROR -----------------------------
#10 6447.0     https://hunter.readthedocs.io/en/latest/reference/errors/error.external.build.failed.html
#10 6447.0 ------------------------------------------------------------------
#10 6447.0
#10 6447.0 CMake Error at /root/.hunter/_Base/Download/Hunter/0.23.249/d45d77d/Unpacked/cmake/modules/hunter_error_page.cmake:12 (message):
#10 6447.0 Call Stack (most recent call first):
#10 6447.0   /root/.hunter/_Base/Download/Hunter/0.23.249/d45d77d/Unpacked/cmake/modules/hunter_fatal_error.cmake:20 (hunter_error_page)
#10 6447.0   /root/.hunter/_Base/Download/Hunter/0.23.249/d45d77d/Unpacked/cmake/modules/hunter_download.cmake:623 (hunter_fatal_error)
#10 6447.0   /root/.hunter/_Base/Download/Hunter/0.23.249/d45d77d/Unpacked/cmake/projects/thrift/hunter.cmake:76 (hunter_download)
#10 6447.0   /root/.hunter/_Base/Download/Hunter/0.23.249/d45d77d/Unpacked/cmake/modules/hunter_add_package.cmake:62 (include)
#10 6447.0   CMakeLists.txt:62 (hunter_add_package)
#10 6447.0
#10 6447.0
#10 6447.0 -- Configuring incomplete, errors occurred!
#10 6447.0 See also "/tmp/tmp.G3XKjcBs3T/jaeger-cpp-client/.build/CMakeFiles/CMakeOutput.log".

[lucacome]

I see there's already an issue about arm #91 and jaegertracing/jaeger-client-cpp#151