ref(metrics): remove features and code related to the old metrics beta

[lcian]

Removes features and code related to the old metrics beta.
Since metrics have been deprecated from the product a few months ago, we can remove the features and code directly instead of deprecating them first.

I have checked and Relay (which uses the sentry-types crate) compiles fine with these changes.

Closes #736

Update: we will just deprecate for now and then wait for sentry-cli to release a major so we can remove all the APIs

[Swatinem]

we can remove the features and code directly instead of deprecating them first.

keep in mind we still need a semver-major (aka minor version as we are [perpetually] 0.X)

Relay (which uses the sentry-types crate)

I’m surprised it does. Do you know what for exactly?

Probably the more interesting thing to test would be sentry-cli, which uses the SDK to submit demo/test events.

[lcian]

we can remove the features and code directly instead of deprecating them first.

keep in mind we still need a semver-major (aka minor version as we are [perpetually] 0.X)

Sure. I then changed my mind and I was thinking to deprecate the feature first and that's why I turned this PR into a draft.

Relay (which uses the sentry-types crate)

I’m surprised it does. Do you know what for exactly?

It's only used here: https://github.com/getsentry/relay/blob/3dfdba91c534877f4623a76e6dcd187a4caf2c00/relay-common/src/lib.rs#L14

Probably the more interesting thing to test would be sentry-cli, which uses the SDK to submit demo/test events.

Good catch.
Indeed, the CLI still has some metrics APIs with a deprecation warning, saying that they will be removed in the next major.

With this information, I would just add deprecation warnings to the SDK, then wait for the next sentry-cli major to completely remove the code and crate feature from the SDK.
This way they will still be able to use the latest version of the SDK.

[Swatinem]

With this information, I would just add deprecation warnings to the SDK, then wait for the next sentry-cli major to completely remove the code and crate feature from the SDK.

TBH, I consider these usages within sentry-cli as really bad. The SDK is not made for that usecase, and sentry-cli should probably use some raw envelope items or some other way, instead of using the SDK "as an SDK" to do this.