Suggested reviewers register project gRPC client

What does this MR do and why?

Register project to suggested reviewer

Related to #373013 (closed)

How to set up and validate locally

1. Run the recommender-bot-service
2. Update the rpc link for local dev
3. On bin/rails c try

c = Gitlab::AppliedMl::SuggestedReviewers::Client.new

d = c.register_project(project_id: 15238759, project_name: 'food', project_namespace 'bar', access_token: 'secret')

MR acceptance checklist

This checklist encourages us to confirm any changes have been analyzed to reduce risks in quality, performance, reliability, security, and maintainability.

• I have evaluated the MR acceptance checklist for this MR.