Add prune old peers functionality for crawler

[cmmarslender]

Keeps the database size and write times under control

Purpose:

Currently, the crawler DB will grow infinitely over time. We used to run similar queries when backing up the crawlers, and since they were recreated periodically, our DBs were mostly kept under control. This moves that pruning to the actual crawler's areas of responsibility, and benefits others running the crawler.

[hoffmang9]

Hell to the yes.

[github-actions]

File	Coverage	Missing Lines
chia/seeder/crawl_store.py	94.4%	lines 424
chia/seeder/crawler.py	33.3%	lines 96-97, 309, 311

Total	Missing	Coverage
49 lines	5 lines	89%

[coveralls-official]

Pull Request Test Coverage Report for Build 9947688177

Warning: This coverage report may be inaccurate.

This pull request's base commit is no longer the HEAD commit of its target branch. This means it includes changes from outside the original pull request, including, potentially, unrelated coverage changes.

• For more information on this, see Tracking coverage changes with pull request builds.
• To avoid this issue with future PRs, see these Recommended CI Configurations.
• For a quick fix, rebase this PR at GitHub. Your next report should be accurate.

Details

• 44 of 49 (89.8%) changed or added relevant lines in 4 files are covered.
• 218 unchanged lines in 7 files lost coverage.
• Overall coverage decreased (-0.2%) to 90.75%

---

Changes Missing Coverage	Covered Lines	Changed/Added Lines	%
chia/seeder/crawl_store.py	17	18	94.44%
chia/seeder/crawler.py	2	6	33.33%

Files with Coverage Reduction	New Missed Lines	%
chia/_tests/core/full_node/test_transactions.py	1	99.11%
chia/server/server.py	2	82.21%
chia/_tests/core/test_farmer_harvester_rpc.py	2	98.02%
chia/full_node/full_node.py	8	85.71%
chia/seeder/peer_record.py	33	45.38%
chia/seeder/crawl_store.py	73	46.89%
chia/seeder/crawler.py	99	33.62%

Totals
Change from base Build 9946298621:	-0.2%
Covered Lines:	101290
Relevant Lines:	111538

---

💛 - Coveralls

[cmmarslender]

Coverage drop here is related to specifically NOT running the crawler loop in the background. The loop was causing flaky behavior by doing unexpected crawling tasks in the background and changing the state of the crawl store in the tests in an uncontrolled and unpredictable manner. The "coverage" that was being provided by that running was not true test coverage - nothing is really testing that loop at the moment in a controlled manner.