Resolve autocorrect deprecations

[Earlopain]

Builds in top of #377, just the last commit is specific to this branch.

Closes https://github.com/Shopify/erb_lint/issues/368

This is pretty much just a compatibility layer in itself.

Cops here are still declared with the old style (autocorrect instance method for example) but rewriting that all is not trivial and also works just fine

[camertron]

Would love to see this get merged, anything I can do to help?