Bring back 32 bit support on Nextcloud 26

[PVince81]

Tasks

• implement CI for 32bit
• changes that will need reverting:
  • implement setup check to block installing on 32bit (master)
    • remove 32-bit workarounds #34907
  • make admin overview check more clear that 32bit compatibility is removed with nc26 (master and stable25)
    • update 64-bit check wording #34906
      • Revert "update 64-bit check wording" #36587
    • [stable25] update 64-bit check wording #34921
      • Revert "[stable25] update 64-bit check wording" #36631
  • make docs more clear that 32bit compatibility is removed with nc26 (master and stable25)
    • 64-bit is required for NC26 documentation#9274
      • Revert "64-bit is required for NC26" documentation#9615
    • [stable25] 64-bit is required for NC26 documentation#9279
      • [stable25] Revert "64-bit is required for NC26" documentation#9620
  • implement check into updater to block upgrades to nc26 on 32bit (master and stable25)
    • disable upgrades to 26 on 32-bit updater#446
      • Revert "disable upgrades to 26 on 32-bit" updater#464
    • [stable25] disable upgrades to 26 on 32-bit updater#452
      • [stable25] Revert "disable upgrades to 26 on 32-bit" updater#465
    • disable upgrades to 26 for 32-bit #34908
      • Revert #34908 to allow 32bit setups to upgrade to 26 #36588
    • [stable25] disable upgrades to 26 for 32-bit #34922
      • [stable25] Revert #34908 to allow 32bit setups to upgrade to 26 #36593
• implement 32bit tests for things formerly breaking on 32Bit (where not mitigate-able due to technical restrictions)
  • test with each CI run would be fine plus running the whole suite (that would work on 32bit" regularly (i.e. daily or weekly against master/stable*) would be enough to not burn too much CI resources

Regarding the typing, instead of removing typing like for stable25 we should use the union types available thanks to PHP 8 and use int|float.

Running the CI on 32 bits is not that straightforward because Github does not propose it so one has to run a docker in a docker or something along these lines. Need someone with knowledge on CI/docker.

On Drone, 64bit hardware is likely able to run 32bit code.
See "arch" field in https://docs.drone.io/pipeline/configuration/

It should not be too hard to fix once we have proper CI, given we have the PR for stable25 to use as an example of how to fix stuff. That said it seems stable25 is still not passing test suite on 32bits.

Estimate: possibly 2 weeks effort if not more depending on hurdles and whether we need to port Github workflow tests to Drone

@AndyScherzinger @DaphneMuller @come-nc @blizzz

[PVince81]

@come-nc can you update the status, in case there was progress on the revertings ?

[come-nc]

Only reverted the first one in my PR, I checked the boxes with current PR state.

Current CI status in the PR:
Tests: 14429, Assertions: 37379, Errors: 8, Failures: 6, Warnings: 29, Skipped: 42.

On the 8 errors:

• 7 are PHPUnit\Framework\MockObject\UnknownTypeException: Class or interface "OCA\Files_External\Lib\StorageConfig" does not exist from tests/lib/Encryption/UtilTest.php:208. They also fail in my 8.2 testing PR and should be fixed or skipped, but are not related to 32bits
• 1 is ValueError: Epoch doesn't fit in a PHP integer from sabre-dav, needs investigation and fix or skip

On the 6 failures:

• All 6 of them seem related to the routes loading failing for files application. From what I was able to debug the include_once in lib/private/Route/Router.php does not include the routes because the file was already included but the routes were lost for some reason. It only happens in github and not in drone or local run, and only happens when running apps/files tests after core tests. So some kind of env specific loading problem. Not related to 32bits. Not clear how to fix it and not sure if safe to skip routing tests on 32bits?

[come-nc]

• Allow float sizes for 32bit support sabre-io/dav#1444