We want to be able to build all the generated sources and the compile_commands.json with a single simple bazel command.

This ticket is for adding "gen_source" tag to all generated sources. This will mostly be covered by using a macro for generated source rules and adding the tag in the macro when the rule is invoked.

ideally in enough time the command would look like:

bazelisk build --build_profile=compiledb --build_tag_filters=gen_source //:compiledb //src/...