Task: simplify uses of createFailure

[andy-hanson]

As of #1845, noUnusedVariableRule.ts and objectLiteralKeyQuotesRule.ts are the only rules using createFailure directly. We should look into simplifying these.

edit: other rules using createFailure:

• banTypesRules.ts
• importSpacingRule.ts
• noFloatingPromisesRule.ts
• noStringThrowRule.ts

[nchen63]

we can remove the deprecated functions now.

[nchen63]

having second thoughts on removing the deprecated functions, which would break almost all 3rd party rules. I think we should leave these in.

[adidahiya]

@nchen63 that's a good point; let's add a deprecation warning in the console in 5.0 though?

[nchen63]

taking out of 5.0 release since we can deprecate later in 5.x, and we're still using the addFailure in some files

[adidahiya]

fair enough