Fix issues with Keystone auth v3 in files_external app

[jlutran]

This PR fixes some issues with Keystone auth v3 in files_external app :

• Keystone auth v3 requires a scoped authorization payload (already fixed for primary storage in ba71918.
• Tenant (project) name parameter was missing.
• Region parameter is mandatory, because of this check.

Fixes #5882
Fixes #11264

[alejandroscf]

I've just tested in Nextcloud 17.0.3 and this works.

As you may already know OVH is turning off auth v2 for their swift storage next month, so probably many nextcloud admins will need this change to work also in Nextcloud 17 and 18 soon. It would be great if this change could be included in the next releases of 17 and 18, maybe that's whats going to happen anyway as I'm not familiar with the release process.

[babolivier]

Any news about support for this in Nextcloud 17 and 18?

[rlamarche]

Well done, working for me too. The strange thing is that I made it working even without applying this pull request to my nextcloud, just by updating the current configuration and putting "Default" in domain, and no tenant name in any visible fields.
By the way I prefer to apply this patch to be sure.

[ChristophWurst]

🐘

[MorrisJobke]

Unrelated CS failures:

Loaded config default from "/home/runner/work/server/server/.php_cs.dist".
6
   1) lib/private/Files/Stream/HashWrapper.php
7
   2) tests/lib/Files/Stream/HashWrapperTest.php

I will submit them in a separate PR.

[welcome]

Thanks for your first pull request and welcome to the community! Feel free to keep them coming! If you are looking for issues to tackle then have a look at this selection: https://github.com/nextcloud/server/issues?q=is%3Aopen+is%3Aissue+label%3A%22good+first+issue%22

[hregis]

Hello
it's possible to include this fixes in the next release of 18.x version please ?
Thanks

[icewind1991]

/backport to stable18