Handle non-pretty URLs for federated server URL

[SystemKeeper]

Ref:

spreed/src/utils/signaling.js

Line 1186 in d891573

url: this._getBackendUrl(this.settings.federation.nextcloudServer),

Since we don't include a possible index.php for nextcloudServer:

spreed/lib/Controller/SignalingController.php

Line 242 in f00266d

'nextcloudServer' => $room->getRemoteServer(),

There is a possibility, that the remote server does not support pretty URLs and signaling federation fails, because the requests can't be made.

This the URL is generated here in talk:

spreed/src/utils/signaling.js

Lines 980 to 982 in d891573

	Signaling.Standalone.prototype._getBackendUrl = function(baseURL = undefined) {
	return generateOcsUrl('apps/spreed/api/v3/signaling/backend', {}, { baseURL })
	}

And here in the lib:
https://github.com/nextcloud-libraries/nextcloud-router/blob/5b8e1711fbaaf9d5f8a68514f741f46361b69570/lib/index.ts#L118-L141

It seems we could just pass noRewrite: true as options, to always have an index.php in the URL, as currently it is determined by our own server support.
This also needs to be done on the clients.

[SystemKeeper]

ocs calls don't use index.php -> no issue here.

[nickvergessen]

That being said, iirc federation doesn't work at all atm without beautiful urls: nextcloud/server#41234

[SystemKeeper]

Ah right, the removal of the ocm-provider directory...