logs: Remove Events operations in favor of making whole Logger user-facing

[pellared]

Fixes #4234
Fixes #4275
Fixes #4199

This PR fixes more issues while making the design simpler than:

• Support complex attributes in the Event API #4334

It does not break anything which was agreed on in https://github.com/open-telemetry/opentelemetry-specification/blob/main/oteps/0265-event-vision.md.

I think we have gathered enough use cases to make emitting log records user-facing:

• Define whether instrumentations can emit non-event log records #4234

Other related OTEP PR:

• OTEP: Recording exceptions as log based events #4333

Here is an OTel Go prototype pre-approved by @open-telemetry/go-maintainers :

• [Prototype] log: Events support with minimal non-breaking changes opentelemetry-go#6018

I want to add that the other prototype following the current specification was not found acceptable for OTel Go SIG:

• [Prototype] log: Events support literally following spec opentelemetry-go#6017