[avalanche] Answer getavaproofs message with short proof ids
This diff introduces a new getavaproofs message, which which requests for an avaproofs message containing all the proofs short ids from the peer.
- The name does not contain the "compact" mention like one might expect, due to the limitation in the command name to 12 chars.
- There is a theoretical limit of 21 millions proofs which could cause the node to generate a oversized message (limited to 2MiB). This will be taken care in a follow-up.
Depends on D11453.
ninja all check-all
Reviewers: #bitcoin_abc, sdulfari
Reviewed By: #bitcoin_abc, sdulfari
Subscribers: sdulfari, deadalnix, tyler-smith
Differential Revision: https://reviews.bitcoinabc.org/D11388