This adds an option to the "Select Similar" operator in edit mode to
select vertices based on vertex crease similarity. The implementation
follows that of the edge crease, with a 1-dimensional KD-tree used to
store and retrieve vertex indices base on crease values.
To maintain compatibility with old files (scripts), the `SIMEDGE_CREASE`
enumeration identifier remains `CREASE`, while the one for the new
`SIMVERT_CREASE` is `VCREASE` to follow the naming convention of other
enum values.
Reviewed By: campbellbarton
Differential Revision: https://developer.blender.org/D14037
8abd8865d2