added models: discount_codes, event_sub_types, event_types, events, groups, microlocation, session_types, sessions, tickets, tracks, video_streams

[PaperBoardOfficial]

Fixes #9104 #9106 #9109

Short description of what this resolves:

Changes proposed in this pull request:

• added following models:
  discount_codes
  event_sub_types
  event_types
  events
  groups
  microlocation
  session_types
  sessions
  tickets
  tracks
  video_streams

Checklist

• I have read the Contribution & Best practices Guide and my PR follows them.
• My branch is up-to-date with the Upstream development branch.
• The unit tests pass locally with my changes
• I have added tests that prove my fix is effective or that my feature works
• I have added necessary documentation (if appropriate)

• All the functions created/modified in this PR contain relevant docstrings.

[marcoag]

Hi @learner-mohit, thanks for the great work! I'm reviewing this. In the meantime can we have a title that is a bit more descriptive?