Enable registration api

[Rinary1]

Re-enables registration api with security fixes, summary:

1. Added Email Validation for Registration and Confirmation.
2. Added Password minimal and maximum length(from 6 to 100, same as on page)
3. Added username minimal and maximum length(from 3 to 32, added to registration page)
4. Added rate limits for registration and confirmation:
   • 2 per hour for confirmation.
   • 5 per 15 minutes for registration.
5. Added security notice when user tries to register account on already registered email.
6. Fixed issue when confirmation can be sent on already confirmed email.

Makes some "out of topic" changes so as not to undermine "general equality":

1. Added Rate Limits for Reset Password and Authenticate.
2. Removed commented out code(nitpick).
3. Added Message in Bed Request in Authenticate(nitpick).
4. Added Email Validation for Reset Password.
5. Added dummy user check in Unauthorized path so that the response times are roughly the same.
   (The same approach as with the Security Notice; its purpose is simply to make the response times for successful and unsuccessful requests roughly the same, because before, unsuccessful response was faster)

Create conflicts with #2.

[StarlightHost]

   // Console.WriteLine(Request.Headers["SS14-Launcher-Fingerprint"]);
    // Console.WriteLine(Request.Headers["User-Agent"]);

Why was this removed?

[Rinary1]

   // Console.WriteLine(Request.Headers["SS14-Launcher-Fingerprint"]);
    // Console.WriteLine(Request.Headers["User-Agent"]);

Why was this removed?

I'm not sure if this is that important, for me it looks like dead code. If anyone needs to debug it, they can just add it locally, right?