EPIC: Partitioned Table UI improvements

[dsmmcken]

Summarizing changes to be made:

• Fix table dying under the agg condition (DH-17242: PartitionedTable display widget does not render properly when there are non-key, non-constituent columns #2066)

New changes For Partitioned Tables:

• Replace the keys table, with a view of the underlying "table" (which includes additional columns) #2103
• Re-name the "keys" button as "Partitions", and remove the "Partitioned Table" label. #2104
• Make the "Partitions" table shown by default #2105
• Allow double clicking on said table to populate the selected keys drop downs #2106
• Add context menu to rows in said table "View constituent table" as last item in list performing same action #2107

New changes for Partitioned Aware Source Table

• Default view should remain as current (selecting the last key for each drop down) #2108
• Re-label merge as "Coalesce" (UI should differentiate between Partitioned Tables and Partition-Aware Source Tables #2049)
• Inherit the above changes to "keys" table ("Partitions") #2109

[AkshatJawne]

Close to completing all enhancements outlined in epic, currently working through adding double click functionality through a mouse handler.

[AkshatJawne]

Only have merged in Java side changes, UI changes still in review / adding functionality for empty table bug