Add python packages required by mkdocs into docker container (#1796)

Add PIP python packages required by mkdocs into docker container

scripts/IronOS.Dockerfile

@@ -14,14 +14,13 @@ WORKDIR /build/ironos
 ## - clang (required for clang-format to check C++ code formatting)
 ## - shellcheck (to check sh scripts)
 
-ARG APK_COMPS="gcc-riscv-none-elf gcc-arm-none-eabi newlib-riscv-none-elf \
-               newlib-arm-none-eabi"
+ARG APK_COMPS="gcc-riscv-none-elf gcc-arm-none-eabi newlib-riscv-none-elf newlib-arm-none-eabi"
 ARG APK_PYTHON="python3 py3-pip black"
 ARG APK_MISC="findutils make git diffutils zip"
 ARG APK_DEV="musl-dev clang bash clang-extra-tools shellcheck"
 
-# PIP packages to check & test Python code
-ARG PIP_PKGS='bdflib flake8'
+# PIP packages to check & test Python code, and generate docs
+ARG PIP_PKGS='bdflib flake8 pymdown-extensions mkdocs mkdocs-autolinks-plugin mkdocs-awesome-pages-plugin mkdocs-git-revision-date-plugin'
 
 # Install system packages using alpine package manager
 RUN apk add --no-cache ${APK_COMPS} ${APK_PYTHON} ${APK_MISC} ${APK_DEV}
@@ -32,4 +31,5 @@ RUN python3 -m pip install ${PIP_PKGS}
 # Git trust to avoid related warning
 RUN git config --global --add safe.directory /build/ironos
 
+# Copy the whole source tree working dir into container
 COPY  .  /build/ironos