Add SlicerMouseMaster extension

Advanced mouse button customization for multi-button mice with preset
management and context-sensitive bindings.

Homepage: https://benzwick.github.io/SlicerMouseMaster
Repository: https://github.com/benzwick/SlicerMouseMaster

Author: benzwick

SlicerMouseMaster.json

@@ -0,0 +1,6 @@
+{
+  "$schema": "https://raw.githubusercontent.com/Slicer/Slicer/main/Schemas/slicer-extension-catalog-entry-schema-v1.0.1.json#",
+  "scm_url": "https://github.com/benzwick/SlicerMouseMaster.git",
+  "scm_revision": "main",
+  "category": "Utilities"
+}