Remove otelkit

[pellared]

Problem Statement

1. The instrumentation is VERY go-kit specific it does not follow any OpenTelemetry Semantic Conventions (e.g. for HTTP)
2. OTel maintainers and approvers are on low capacity and lack expertise on go-kit. See:

   opentelemetry-go-contrib/CODEOWNERS

   Line 36 in 9437f9b

   instrumentation/github.com/go-kit/kit/otelkit/ @open-telemetry/go-approvers

3. Tther tracing instrumentation can be found under https://github.com/go-kit/kit/tree/master/tracing
4. The currently preferred way according to our recommendation is to no not have the instrumentation in this repository

Proposed Solution

Deprecate https://github.com/open-telemetry/opentelemetry-go-contrib/tree/main/instrumentation/github.com/go-kit/kit/otelkitin next release.

Afterwards, as part of a subsequent release, remove the module from codebase and from the OTel Registry (https://opentelemetry.io/ecosystem/registry/adding/)

Additional Context

See go-kit/kit#1266

[pellared]

Closing per #4295