Exclude Gitaly unavailable error from error rate
This merge request does 3 things:
- Display constistently in gitlab-sshd and gitlab-shell
- Use console package to format the errors in gitlab-sshd
- Suppress internal Gitaly errors in client output
- Exclude Gitaly unavailable error from error rate
When a user hits repository rate limit, Gitaly returns an error that the request can't be handled (Gitaly unavailable). We should avoid this error to avoid exceeding the error rate
- Downgrade auth EOF messages from warning to debug
The errors happen when a client closes a connection on handshake. They can be ignored to avoid noise