feat(config): move EOL date to config.php instead of boolean

[Altahrim]

EOL flag is now computed when serving response

Pro

• Will send EOL flag as soon as EOL date is reached, without changing the config.php
• Add EOL date as info for Nextcloud

Cons

• Any major split with XX.Y and XX.Z will not have different EOL.
  For instance, 27.0 couldn't be EOL if 27.1 isn't. This could be improved later.

[blizzz]

Any major split with XX.Y and XX.Z will not have different EOL.
For instance, 27.0 couldn't be EOL if 27.1 isn't. This could be improved later.

That's not necessary, it is the same series.

[blizzz]

Good with me!

[nickvergessen]

That's not necessary, it is the same series.

Security wise it's actually the opposite. 27.0 was EOLed by the release of 27.1.0