Metric Drain Support for Sentry Metrics

You can now send trace-connected metrics to Sentry! See the docs [here](https://docs.sentry.io/product/explore/metrics/).

Currently you need to use one of our SDKs to send metrics, but we're exploring the use case of Metric Drains. This issue tracks supporting metric drain providers.

If you're interested in metric drain support, please leave a react on this GitHub issue. That will help us prioritize this accordingly. We created some child issues to track popular providers, but if there is a provider missing let us know and we'll open a new issue for it.

No source files, tests, or entry points are identified. Start with the Sentry Metrics documentation linked in the issue and review the existing child issues for provider-specific scope. Done would mean implementing and validating support for a selected metric drain provider, but the provider and acceptance criteria are not yet specified.

Written by the indexing model from the issue text.