Add KV Filtering of keys

[darkwatchuk]

Resolves #521

[mtmk]

LGTM thanks @darkwatchuk

[rickdotnet]

@mtmk , how important is this bit from the ADR? It looks as though it doesn't impact this implementation. Just making sure we don't need an additional check.

// When multiple filters are passed, client library should check `consumer info` from `consumer create method` if the filters are matching,
// as nats-server < 2.10 would ignore them.

[mtmk]

@mtmk , how important is this bit from the ADR? It looks as though it doesn't impact this implementation. Just making sure we don't need an additional check.

// When multiple filters are passed, client library should check `consumer info` from `consumer create method` if the filters are matching,
// as nats-server < 2.10 would ignore them.

@rickdotnet good point. created an issue for it:

• Check multiple KV filters against consumer info #546