Stop ignoring some peers when updating the address book

[teor2345]

Motivation

Zebra was ignoring some peers when updating the address book.

This could be the cause of issues like #3042.

Solution

• Correctly apply MetaAddrChanges when there is no existing address book entry
• Add all initial peers to the address book (not just the unused ones)

Review

This PR is ready for review.

I think @dconnolly can review this PR.

Reviewer Checklist

• Code implements Specs and Designs
• Tests for Expected Behaviour
• Tests for Errors

I've tested this PR locally, and the crawler and address book metrics look a lot better. The number of peer addresses rises rapidly, and gets full after a few hours. And Zebra doesn't hang any more, even after a few days.

[codecov]

Codecov Report

Merging #3292 (bf569a6) into main (144c532) will increase coverage by 0.11%.
The diff coverage is 95.45%.

@@            Coverage Diff             @@
##             main    #3292      +/-   ##
==========================================
+ Coverage   77.10%   77.21%   +0.11%     
==========================================
  Files         265      265              
  Lines       31460    31462       +2     
==========================================
+ Hits        24256    24293      +37     
+ Misses       7204     7169      -35     

[teor2345]

I've tested this PR locally, and the crawler and address book metrics look a lot better. The number of peer addresses rises rapidly, and gets full after a few hours. And Zebra doesn't hang any more, even after a few days.

[teor2345]

Marking as a high priority, because this bug sometimes makes CI fail.

[dconnolly]

lgtm!