Change the terminology in UI for index storage mode and index write mode

after customer and field discussion we have found the following terminology work best for the new options added to GSI for new storage and write mode in the UI.
there are 2 changes - we now clearly label fdb based index storage options "Standard Global Secondary Index" and moi as "Memory Optimized Global Secondary Index". We also stop using circular compaction and instead explain the new write modes as append-only vs circular writes with new test to explain the options in the UI.
Docs will also reflect the changes for GA. let me know if you have questions.
-cihan

NEW UI LABELS:
Index UI Settings > Cluster
Cluster/Index Service Initialize Settings

• Index Settings
• -------------------
• Index Storage Mode:
  o Standard Global Secondary Indexes
  o Memory-Optimized Global Secondary Indexes

Index UI Settings > Auto-Compaction

• Index Fragmentation
• ---------------------------
• Write Mode:
  o Append-only Write Mode with index fragmentation level to determine the point when compaction is triggered (default 30%)
  o Circular Write Mode with time interval for when compaction is allowed to run (default every night at start time 00:00)