* feat: update lightpush API to make pubSubTopic optional as per autosharding
* Extract contentFilter and subscriptions out of filter to reuse in relay (#779)
* chore: extract contentFilter outside filter package
* chore: move subscription outside of filter so that it can be modified and reused for relay
* Feat: filter select peer for sharding (#783)
* update selectPeer to support pubsubTopic based selection
* feat: update filter client to support autosharding
* chore: add filter tests for autoshard
* chore:update filter API docs for autosharding
* chore: docs changes to indicate sharding impact on pubSubTopic
* fix: handle partial errors during subscribe and return failed content-topic details