Allow specifying of mobile app deep link domains instead of only http(s) domains in websiteDomain

[rishabhpoddar]

• This would be useful for someone making a mobile app
• Maybe we should add another field for that instead of calling it websiteDomain. We can call it something like deepLlinkDomain? Only one of these can be provided, and the logic for cookie config should be changed in accordance to which is provided.
• Furthermore, we should change the app info form in the docs to add deepLlinkDomain or websiteDomain by asking them to check if it's a mobile app frontend or backend.

If someone is using both, a mobile app and a website, that is a case for multi tenancy and should be solved via that.