tv-casting-app: KVS storage management improvements

[sharadb-amazon]

Problem

The tv-casting-app requires clearing of the KVS based storage if it was commissioned on a previous run. This is required on Linux, Android and iPhone

Proposed Solution

Research and implement a way so that the app cache does not need to be cleared from settings to redo the commissioning process

[sharadb-amazon]

As part of this issue, add support to purge fabrics stored locally.