Task formatKotlin should fail build if it cannot fix all lint errors

[acreddy9]

This issue is the inverse of issue #335.

It is slightly misleading when the formatKotlin task build succeeds with unfixed lint errors. This can be solved by adding an optional configuration so users can choose whether the formatKotlin task build succeeds (default) or fails when it is unable to autoformat all lint errors detected. The configuration should be overrided by the ignoreFailures configuration, such that if ignoreFailures is set to true then the build will always succeed. We actually have this solution ready and can make a PR, but wanted to open this issue first to provide an explanation and receive any initial feedback :)

[juliakispert]

We would love any feedback on the PR or issue. Thank you in advance!

[jeremymailen]

Sorry about the delay. It's been extraordinarily busy this past month. I do plan to get the pending changes reviewed and a new version out, but it might be a few days before I can get to it.

[jeremymailen]

Will incorporate into 4.1.0.