Issue/createroom api behavior does not match spec

[tristianc]

Pull Request Checklist

• I have added Go unit tests or Complement integration tests for this PR or I have justified why this PR doesn't need tests
• Pull request includes a sign off below or I have already signed off privately

Signed-off-by: Tristian Celestin <[email protected]>

[CLAassistant]

All committers have signed the CLA.

[kegsay]

I would prefer it if you just set the createRequest.StatePreset rather than re-implement the state preset code here.

i.e:

// If unspecified, the server should use the visibility
// to determine which preset to use.
// A visibility of public equates to a preset of public_chat
// and private visibility equates to a preset of private_chat.
if createRequest.StatePreset == "" {
    switch createRequest.Visibility {
        // Rooms default to private visibility if this key is not included.
        case "private", "":
            createRequest.StatePreset = "private_chat"
        case "public":
            createRequest.StatePreset = "public_chat"
    }
}

switch createRequest.StatePreset {
// ... rest of code

[kegsay]

Otherwise LGTM