feat(relay): add configuration option to allow high cardinality tags in metric calls

[Litarnus]

This PR adds a configuration option to allow high cardinality tags, such as project id, in metrics.
High cardinality tags are prefixed with hc.. By default, it will always strip those tags.

ref INGEST-140

[Dav1dde]

This allows adding high cardinality tags to metrics which are removed at a central place instead of having to modify metrics calls individually.

What is your plan with this? The tags should be opt-in not opt-out, this config looks like it would be more for opt-out?

Exposing all this functionality doesn't seem like a great idea, if we don't have to. People can also filter on their statsd service or collector.