TX Submission Logic

[coot]

Description

This is a draft PR (work in progress) which introduces tx-submission logic responsible for choosing from which peer to download a tx.

Checklist

Quality

• [ ] Commit sequence makes sense and have useful messages, see ref.
• [ ] New tests are added and existing tests are updated.
• [ ] Self-reviewed the PR.

Maintenance

• [ ] Linked an issue or added the PR to the current sprint of ouroboros-network project.
• [ ] Added labels.
• [ ] Updated changelog files.
• [ ] The documentation has been properly updated, see ref.