new rule: unneeded mocha done

[HamletDRC]

If an it/describe/before/after function takes a MochaDone parameter, then it should really be needed.

Create a violation if:

• a mocha lifecycle function declares a mocha done parameter
• the done parameter never escapes the method (as a parameter to a function, for example)
• the done object is only invoked once as the last line of the function

[michalzubkowicz]

Isn't it causing false positive when async/await is used?