(Delegator) Add endpoint to retrieve eoa addr

[nick-bisonai]

Description

Adds endpoint which returns fee payer public address, to be referenced from orakl-sentry

Type of change

Please delete options that are not relevant.

• [ ] Bug fix (non-breaking change which fixes an issue)
• [x] New feature (non-breaking change which adds functionality)
• [ ] Breaking change (fix or feature that would cause existing functionality to not work as expected)
• [ ] This change requires a documentation update

Checklist before requesting a review

• [x] I have performed a self-review of my code.
• [ ] If it is a core feature, I have added thorough tests.

Deployment

• [ ] Should publish npm package
• [ ] Should publish Docker image