[avalanche] Add a peer replacement cooldown

Summary:
This adds up the last missing cooldown feature. This prevents a malicious actor from updating a proof with a better one in a short time frame (dfefault 1h).

Ref T1854.

Depends on D10788.

Test Plan:

ninja all check-all

Reviewers: #bitcoin_abc, tyler-smith

Reviewed By: #bitcoin_abc, tyler-smith

Subscribers: tyler-smith

Maniphest Tasks: T1854

Differential Revision: https://reviews.bitcoinabc.org/D10789