Describe table partition stats fetch should be configurable

In certain 3rd party hive UIs, they issue a describe table command, and usually it's either "describe formatted table" or "describe extended table", and it will take a very long time for highly partitioned tables (10k+). In the UI, there is no way to change the settings (to use "describe table"), thus impairing the user experience. Prior to the feature where partition stats was gathered, the experience with using the UI had no problems.

This will allow users to selectively change the describe formatted/extended table behavior at any time.

The setting will be:
hive.describe.partitionedtable.ignore.stats = false; – default behavior (no user impact)