Remove legacy authentication

[jasondilworth56]

It is no longer possible to login with username/password combinations, so that option should be removed.

• Include removal of tests
• Remove documentation

[tristanduncombe]

Hi @jasondilworth56,

I have address this in my fork of this repo. I'm just waiting on iRacing to get back to me with my oAuth token. I spent hours debugging my code on why my legacy auth wasn't working!

You're more than welcome to steal that and change it any way you would like. I can PR it - but I'd prefer not to until I can test with an oAuth token.

[jasondilworth56]

No major rush @tristanduncombe - take your time and it's ready when it's ready. I appreciate you planning to put something forwards.