* Granule purge cannot delete history entry for fully deleting granule until all children are completely done splitting
* Several purging fixes related to granule history
* Fixed typo in refactor
* fixing memory model for purgeRange
* formatting
* weakening granule purge test for now
* cleanup
* First version of force purging granules
* fixing issue in BW range assignment reporting
* Fixing incorrect assert with force purging
* Error handling when checking force purged state
* fixed force purging and recover/reassign range races and check
* Handling force purge + boundary change race
* more places to check for force purged status
* fixed manager restart in the middle of force purge bug
* fixing same-BM purge and assignment races in all cases
* weakening orphaned granule history check a bit because of difficult to solve races
* fixing txn options on retry
* loading force purged ranges at start to avoid resuming a merge that is being force purged
* cleanup
* Enabling purging in granule tests, and adding check for leaked change feeds in force purge
* formatting
* missed parameter in merge conflicts
* Fixing leaked change feed race with merge and force purge
* adding change feed cleanup when new blob manager recovers in-progress merge that raced with force purge
* added forcepurge fdbcli command
