rsky-relay: connect to everything

[utkarshgupta137]

Summary

Added various changes to enable connecting to all PDSes:

• persisted host state on a timer
• retry on host sqlite locked error
• add connect/reconnect backoff
  • TODO: add logic to clear retry once we've a stable connection
  • TODO: persist retry state to DB
• use non-blocking connect for crawler
  • Without this, the crawler worker can get blocked while we're trying to connect & do a handshake
  • With this, we can have try connecting to new hosts without blocking everything
• increased queue sizes to accommodate more hosts

Changes

• Feature implementation
• Bug fix
• Documentation update
• Other (please specify):

Checklist

• I have tested the changes (including writing unit tests).
• I confirm that my implementation aligns with the canonical Typescript implementation and/or atproto spec
• I have updated relevant documentation.
• I have formatted my code correctly
• I have provided examples for how this code works or will be used