Remove things that are officially marked as deprecated

[JeanChristopheMorinPerso]

A couple of years ago, some modules were renamed and the old modules were kept there, but marked as deprecated. Python raises a DeprecationWarning when they are imported.

We also have some CLI flags and other thing here and there that raise deprecation warnings.

We should remove them in the next major version.

Modules:

• rez.packages_
• rez.package_resources_
• rez.package_maker__
• rez.build_process_

Other:

• rez/src/rez/cli/pip.py

  Line 62 in ab317e6

  warnings.warn(

• rez/src/rez/build_process.py

  Line 82 in ab317e6

  working_dir (DEPRECATED): Ignored.

• rez/src/rez/cli/search.py

  Line 62 in ab317e6

  help="print results in sorted order (deprecated)")

• bez:

  rez/src/rez/build_system.py

  Line 81 in ab317e6

  # Special case - bez. This is an old deprecated build system,

• rez/src/rez/rex.py

  Line 1422 in ab317e6

  this code. DEPRECATED - use `self.reset_globals` instead.

• Ability to load old package YAML definitions. (see calls to

  rez/src/rez/serialise.py

  Line 109 in 371644d

  def load_from_file(filepath, format_=FileFormat.py, update_data_callback=None,

  ).

• rez/src/rezplugins/package_repository/filesystem.py

  Line 211 in 371644d

  def _load_old_formats(self):

• Ability to write RXT file in YAML instead of JSON.