* Add input validation for bot tokens based on their length
* Add token validation to BaseDiscordClient#LoginAsync
Adds a TokenUtils class which is used to validate that tokens are correct
* Revert changes to DiscordRestApiClient
* Add Unit tests to the TokenUtils class, fix a logic error that was caught by those tests
* Allow for API to throw exceptions
Moves the validation of tokens to be inside of LoginInternalAsync, and writes a Warning to the console when the supplied tokens are invalid
Chris Johnston