Watch for certificate files updates in ConfigReloader

[myrrc]

Changelog category (leave one):

• Improvement

Changelog entry (a user-readable short description of the changes that goes to CHANGELOG.md):

Update certificates when they change without the need to manually SYSTEM RELOAD CONFIG

[robot-ch-test-poll1]

This is an automated comment for commit d0f81fb with description of existing statuses. It's updated for the latest CI running
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The overall status of the commit is 🟢 success

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[myrrc]

Things to consider: path to certificate changed, needs updating from inside the reloader itself.
I believe in that case user could run RELOAD CONFIG manually.

[myrrc]

Another (better option) -- run an update callback on configReloader creation having lvalue ref to the reloader, and move certificateReloader inside configReloader callbacks everywhere. Will update PR tomorrow

[alexey-milovidov]

LGTM.
It does not have a test. Let's proceed without a test (but you agree that the feature can be broken or removed)