[clang-tidy] Extend spelling for CheckOptions

The current way to specify CheckOptions is pretty verbose and unintuitive.
Given that the options are a dictionary it makes much more sense to treat them as such in the config files.
Example:
```
CheckOptions: {SomeCheck.Option: true, SomeCheck.OtherOption: 'ignore'}
# Or
CheckOptions:
  SomeCheck.Option: true
  SomeCheck.OtherOption: 'ignore'
```

This change will still handle the old syntax with no issue, ensuring we don't screw up users current config files.

The only observable differences are support for the new syntax and `-dump=config` will emit using the new syntax.

Reviewed By: aaron.ballman

Differential Revision: https://reviews.llvm.org/D128337