Decomission of scripts/ci

[ia]

• Please check if the PR fulfills these requirements

• The changes have been tested locally
• There are no breaking changes

• What kind of change does this PR introduce?
  Remove out-of-dated files.

• What is the current behavior?
  Directory scripts/ci contains two md5 files which, as far as I understand, some legacy files from the previous way of preparing env & compiling firmware (probably, sums used to make sure that the proper toolchains are used) and one shell script which could be easily replaced by make target for unification of the build system.

• What is the new behavior (if this is a feature change)?

• scripts/ci is removed completely
• build-all target implemented in the top-level Makefile
• call of buildAll.sh is replaced by make build-all
• optionally, OUT environmental variable can be provided to set another directory for output, i.e., if for some reason someone would want to copy compiled binaries to scripts/ci/artefacts then just use make build-all OUT=scripts/ci/artefacts or OUT=scripts/ci/artefacts ./scripts/deploy.sh build
• basic possible combinations of calling build-all in updated manner have been tested locally successfully
• default output directory (instead of old scripts/ci/artefacts) is OUT directory right in the IronOS root project directory

• Other information:
  Since I couldn't find any hard-coded values regarding scripts/ci/artefacts I decided to pick more easy-to-find place as default which is OUT directory currently. And for the same reason I guess it shouldn't break anything but bring a bit of more tidiness to files, directory structure & maintainability. Therefore, after this patch there will be only two make files (Makefile & source/Makefile) and only two shell scripts (scripts/deploy.sh & source/build.sh)