feat(api): Move from index.php to ocs API

[nickvergessen]

No description provided.

[nickvergessen]

/backport to stable27

[tobiasKaminsky]

@GretaD or @nickvergessen can we have a bit of documentation?
Mobile team also shall implement it :)

[nickvergessen]

we should do openapi I guess.

---

Until then:

So clients should now be able to get the state:

GET https://nextcloud31.local/ocs/v2.php/apps/terms_of_service/terms

has a data field "hasSigned":false
and then they need to open the frontend if possible
or they show the details from that request
and then send a POST to:

POST https://nextcloud31.local/ocs/v2.php/apps/terms_of_service/sign

should add openapi specs I guess
but at least for the quick fix it should work

[nickvergessen]

OpenAPI added in #1011