PyAPI: Use annotations for RNA definitions

- Logical use of fields since they define type information.
- Avoids using ordered-dict metaclass.

Properties using regular assignments will print a warning and load,
however the order is undefined.

release/scripts/modules/bpy_extras/keyconfig_utils.py

@@ -406,6 +406,7 @@ def keyconfig_test(kc):
             result = True
     return result
 
+
 # Note, we may eventually replace existing logic with this
 # so key configs are always data.
 from .keyconfig_utils_experimental import (