chore: remove ZTools addon from build and loader (#344)

- Remove ZTools install block from src/Mod/Create/CMakeLists.txt
- Remove mods/ztools submodule entry from .gitmodules
- Remove 'ztools' from legacy fallback order in addon_loader.py
- Remove ztools imports and test classes from test_kindred_pure.py
  (TestTypeMatches, TestMatchScore, TestSelectionItemProperties,
   TestColumnToIndex, TestDatumModes)
- Remove 'ztools Workbench' from issue template component lists
- Remove mods/ztools submodule from git tracking

ZTools will be archived to a reference folder in a separate step (#345).
This is part of the UI/UX rework epic (#346).

.gitea/ISSUE_TEMPLATE/feature_request.yml

@@ -27,7 +27,6 @@ body:
       description: Which part of Kindred Create does this relate to?
       options:
         - General / Core
-        - ztools Workbench
         - Silo (Parts Database)
         - Theme / QSS
         - Assembly