Refactor Event API to reflect spec changes

[jack-berg]

Reflects changes in open-telemetry/opentelemetry-specification#3772 and open-telemetry/opentelemetry-specification#3749.

Summary of changes:

• event.domain and event.name attributes merged into event.name, which is expected to be namespaced and follow attribute naming rules. The EventEmitterBuilder#setEventDomain method is deleted.
• Event payload defines what actually occurred in the event. Its represented using an AnyValue type and maps to the log record body. The payload argument is optional, reflecting the fact that some events will only have a event.name.
• Add EventBuilder#setContext method for optionally overriding the default current context.
• Add optional SeverityNumber argument, which defaults to INFO=9. This can be used to sample / filter events according to priority.
• Add EventBuilder#setAttributes method for optionally setting the event attributes. The event payload is expected to be well defined, and the attributes can be used to specify additional information about the context of what occurred.

[codecov]

Codecov Report

Attention: 2 lines in your changes are missing coverage. Please review.

Comparison is base (531898c) 91.18% compared to head (e1459c6) 91.20%.
Report is 28 commits behind head on main.

❗ Current head e1459c6 differs from pull request most recent head ed93763. Consider uploading reports for the commit ed93763 to get more accurate results

Files	Patch %	Lines
...entelemetry/sdk/logs/internal/SdkEventBuilder.java	88.88%	1 Missing and 1 partial ⚠️

Additional details and impacted files

@@             Coverage Diff              @@
##               main    #6001      +/-   ##
============================================
+ Coverage     91.18%   91.20%   +0.02%     
- Complexity     5613     5620       +7     
============================================
  Files           616      618       +2     
  Lines         16566    16579      +13     
  Branches       1642     1643       +1     
============================================
+ Hits          15105    15121      +16     
+ Misses         1013     1008       -5     
- Partials        448      450       +2     

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[jack-berg]

Marking ready for review as the spec PRs this embodies have been merged.

[breedx-splk]

This looks good. I asked about an overload, but we can always add them later. 👍🏻

[jack-berg]

Converted to a draft again because the event sig is actively working out details this PR changes and I want to wait for those discussions to resolve to reduce churn.

[jack-berg]

Closing for the time being until details get hashed out by the event SIG.