Add endpoint/method for getting data requirements for account creation & login

[bczsalba]

Most websites and apps show the criteria usernames & passwords on the account creation screen, which is a really useful set of information to have.

This could be communicated through a json sent by the server:

{
    "password_length": 10,
    "characters": {
        "numeric": True,
        "uppercase": False,
        "lowercase": True,
        "special": False,
    }
}

This can then be parsed by the client, and be displayed in a nice way. These values could be control with the right permissions.

Another advantage of this system would be that it would let some methods reject data before it's even submitted to the server, allowing for much quicker use in general.

[svmorris]

Yes this makes a lot of sense.
I'm thinking that when the method for getting general information about a chatroom is done, It could return this sort of information if the client is not logged in.