Make __version__ attribute consistent in Python modules

[josh-hadley]

AFDKO Python module __version__ attributes are inconsistent. Many don't have the attribute at all; some that do put the module name or date in the version string; others use "X.Y" while others still use "X.Y.Z" versioning.

After other cleanup & trimming is done (drop Python 2.7 support & other related initiatives), remaining Python modules should have consistent versioning applied, and the __version__ attribute should be the single source of truth for the module version (not docstrings or other attributes). I propose the following scheme:

• Format: __version__ = 'X.Y.Z'

• Location: module scope, ideally immediately following imports, before other module attributes, constants, etc.

• How to set the value:

  • modules already using "X.Y.Z" scheme: increment 'Z' for bug/trivial/patch updates. Use 'X.Y+1.0' for minor updates, 'X+1.0.0' for major updates (semantic versioning)
  • modules with versions set in docstrings or other locations: remove from that location & increment (usually Z-value + 1 for minor updates).
  • modules with no version # anywhere: use X.Y.Z == current FDK release version
  • modules using "X.Y" versioning: add Z == 1 (see note above re: semantic versioning)
  • modules using the name, date, or other values in the __version__ attribute should remove those and leave only "X.Y.Z" (incremented as applicable for semantic versioning)

Versioning-related updates can be performed along with other work as needed or as a focused effort.