Merge Dockerfiles directory and Build environments directories

CODEOWNERS

README.md

experimental_official_bazelrcs/README.md

official_build_environments/README.md

official_build_environments/master/linux/Dockerfile

official_build_environments/master/linux/bashrc

...cial_build_environments/master/linux/builder.packages.txt

official_build_environments/master/linux/devel.packages.txt

...al_build_environments/master/linux/devel.requirements.txt

...nvironments/master/linux/devel.user_tools/build_addons.sh

...ld_environments/master/linux/devel.user_tools/build_tf.sh

...ld_environments/master/linux/devel.user_tools/cpu.bazelrc

...ld_environments/master/linux/devel.user_tools/gpu.bazelrc

...nvironments/master/linux/devel.user_tools/mounted.bazelrc

...vironments/master/linux/devel.user_tools/preliminary.bats

...build_environments/master/linux/devel.user_tools/pylintrc

..._environments/master/linux/devtoolset/build_devtoolset.sh

...al_build_environments/master/linux/devtoolset/fixlinks.sh

...l_build_environments/master/linux/devtoolset/rpm-patch.sh

...cial_build_environments/master/linux/devtoolset/update.sh