[avalanche] Introduce a CompactProofs class for managing the short proof ids

Summary:
This class serializes and deserializes the proof short ids. This will be used to send and process the compact proof messages.

Depends on D11450.

Test Plan:

ninja check-avalanche

Reviewers: #bitcoin_abc, deadalnix

Reviewed By: #bitcoin_abc, deadalnix

Subscribers: deadalnix

Differential Revision: https://reviews.bitcoinabc.org/D11453