feat(p2p): add ability to update peer_id.json with SIGUSR1

[glevco]

Motivation

Implement ability to update the full node public IP while the sync is running, as requested in the issue: resolves https://github.com/HathorNetwork/internal-issues/issues/261.

Here are the new ways of interacting with entrypoints and the hostname:

Sysctl hostname command

Get and manually set the full node's hostname. Entrypoints will automatically reflect this change, and connections will be reset.

Sysctl refresh_auto_hostname command

Automatically set the hostname to an auto discovered one. Entrypoints will automatically reflect this change, and connections will be reset.

Sysctl reload_entrypoints_and_connections command

Reload the peer_id.json file, replacing the entrypoints list with the new one. Then, connections will be reset.

SIGUSR1 command

This is just a shortcut to the sysctl reload_entrypoints_and_connections command.

Acceptance Criteria

• Remove CliBuilder.create_peer_id() and add PeerId.create_from_json_path().
• Refactor ConnectionsManager.listen() so it uses the listen deferred and persists the listened addresses.
• Implement ConnectionsManager.update_hostname_entrypoints() and reset_all_connections().
• Move peer_id.json file path to the PeerId class, with the reload_entrypoints_from_source_file() method.
• Add sysctl commands for getting/setting hostname, refreshing the auto hostname, and resetting all connections.
• Add peer_id.json reload in SIGUSR1.

Checklist

• If you are requesting a merge into master, confirm this code is production-ready and can be included in future releases as soon as it gets merged

[codecov]

Codecov Report

Attention: Patch coverage is 43.75000% with 9 lines in your changes are missing coverage. Please review.

Project coverage is 85.10%. Comparing base (23f764d) to head (adc0191).

❗ Current head adc0191 differs from pull request most recent head b9abf07. Consider uploading reports for the commit b9abf07 to get more accurate results

Files	Patch %	Lines
hathor/manager.py	30.00%	7 Missing ⚠️
hathor/p2p/peer_id.py	60.00%	2 Missing ⚠️

Additional details and impacted files

@@           Coverage Diff           @@
##           master     #981   +/-   ##
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  Coverage   85.10%   85.10%           
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  Files         296      296           
  Lines       22902    22909    +7     
  Branches     3447     3449    +2     
=======================================
+ Hits        19490    19497    +7     
- Misses       2728     2732    +4     
+ Partials      684      680    -4     

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[glevco]

@msbrogli @jansegre This PR changed considerably, could you please re-review it?

The description has been updated to reflect new changes. Also, I ended up not implementing the looping call to refresh the auto hostname, and instead just provided a sysctl command to do it. The reason is that the API is currently blocking.