[BP to 6.6.2] - FTS - Too many key writes / tombstones in metakv

During the CC system tests, it is observed that FTS overload the metakv systems with too many keys and tombstone values. More details can be found here - MB-45168, MB-45258

We could try reducing the number of plan computations/writes into the metakv system with a minimum surface area change. 

The number of plan re-computations/writes scales linearly with the number of FTS nodes in the system today and looks like we can fix that by changing the design of planners's working today.