Feature: generate a bzl file with a macro that can be run in MODULE.bazel and sets up the 3rd party maven deps

[menny]

The purpose is to have a standalone bzl file that can load the 3rd-party maven jvm artifacts, instead of relying on mabel extension to do the work.

A new attribute in mabel_rule (optional):
module_mabel_manual_repos_file

This will tell mabel to generate a .bzl file (in the path provided in module_mabel_manual_repos_file) that contains a macro that:

• creates the required http_file calls for all the resolved artifacts
• create required _aar_import_repo, _jvm_import_repo, _maven_alias_repo, java_plugin, etc
• this macro is to be called in a MODULE.bazel file of another bazel workspace.
• the other bazel workspace will not need to use bazel_dep to load mabel, and will not need to run any extensions of mabel.
• the other bazel workspace will only need a copy of the generated module_mabel_manual_repos_file and will call the generated macro in its MODULE.bazel file.