Feature Flag evaluation event

[dyladan]

First draft of feature_flag.evaluation event from the feature flag semantic conventions working group. Based on proposal here: https://docs.google.com/document/d/1sBDD-uifx-Qy0NxtwRcrRAQ48sHQS9dTp6tpArQsoZg/edit

Summary of changes:

• Replace feature_flag.provider_name with feature_flag.provider.id
• Rename feature_flag to feature_flag.evaluation
• Add attributes to feature_flag.evaluation
  • feature_flag.context.id
  • feature_flag.environment.id feature_flag.flag_set.id
  • feature_flag.value
  • feature_flag.version
• Remove feature flag span event

[askpt]

I added a couple of comments; otherwise, it looks good.

[askpt]

I suggest leaving this open. Using an "id" means it is "blocked" only to use IDs, and we can potentially use it for names or other semantically valid values.
I would allow you to use the following examples:
["provider-1", "guid_here", "provider-v1"]

[dyladan]

I'm not sure what you mean by "leaving this open"