Implement INFO command

[internet-catte]

>>> INFO
:server1.test 371 a :Sable --
:server1.test 371 a :
:server1.test 371 a :Copyright (c) 2021-2024 Sable Development Team
:server1.test 371 a :
:server1.test 371 a :This program is free software: you can redistribute it and/or modify
:server1.test 371 a :it under the terms of the GNU Affero General Public License as published
:server1.test 371 a :by the Free Software Foundation, either version 3 of the License, or
:server1.test 371 a :(at your option) any later version.
:server1.test 371 a :
:server1.test 371 a :Source code is available at: https://github.com/Libera-Chat/sable
:server1.test 371 a :
:server1.test 371 a :A list of contributors can be found in the git log.
:server1.test 371 a :
:server1.test 371 a :Visit the Sable website at: https://sable.chat/
:server1.test 371 a :Visit us on IRC at irc.libera.chat #libera-dev
:server1.test 371 a :
:server1.test 371 a :Version: sable-0.1.0-aabc527319a4e9ff2dfb8d1e45ee35e3bbf0116f-dirty
:server1.test 371 a :Commit date: Thu, 23 May 2024 13:48:00 +0000
:server1.test 374 a :End of /INFO list

[spb]

:server1.test 371 a :Build date: Wed, 22 May 2024 22:12:16 +0000

I don't think build date is actually what we want here - the commit date would be far more useful.

[internet-catte]

should the build time be used if the tree is dirty?

[spb]

No, unless you can think of a way it would be meaningfully useful. Commit date is useful because if you're trying to quickly identify which servers do or don't have a given fix applied, you can filter on commit date without needing the git log to know which commit IDs contain the one you're after. Build date doesn't tell you that and can be actively misleading if you're unlucky.