Add release manager persona in feature proposal template

What does this MR do?

Updated the feature proposal comment text to include the updated persona of Rachel (Rachel (Release Manager)) to save some time when adding the relevant personas a feature request would address/serve.

Screenshots

No relevant screen shots

Does this MR meet the acceptance criteria?

Yes

Conformity

• Changelog entry
• Documentation (if required)
• Code review guidelines
• Merge request performance guidelines
• Style guides
• Database guides
• Separation of EE specific content

Availability and Testing

N/A

Security

If this MR contains changes to processing or storing of credentials or tokens, authorization and authentication methods and other items described in the security review guidelines:

N/A