Addon manager: Reduce fetches from GitHub

Reduce the number of GitHub fetches when rebuilding the local addon cache by using a remote cache stored on FreeCAD's servers.

Intended to mitigate the Addon Manager hitting GitHub's rate limiters.

Addresses, but does not fully close, #15059

src/Mod/AddonManager/addonmanager_freecad_interface.py

@@ -63,7 +63,7 @@ except ImportError:
         return string
 
     def Version():
-        return 0, 21, 0, "dev"
+        return 0, 22, 0, "dev"
 
     class ConsoleReplacement:
         """If FreeCAD's Console is not available, create a replacement by redirecting FreeCAD