feat: use cosmiconfig

[nschonni]

Short description of what this resolves: Taking a kick at https://github.com/htmlhint/HTMLHint/issues/126 to better handle malformed configs, and support for other config formats.

Haven't figured how to properly throw/test this yet

Proposed changes:

[stale[bot]]

This issue has been automatically marked as stale because it has not had recent activity. It will be closed if no further activity occurs. Thank you for your contributions.

[stale[bot]]

This issue has been automatically marked as stale because it has not had recent activity. It will be closed if no further activity occurs. Thank you for your contributions.

[MindTooth]

Could this be tweaked to also include support for htmlhint.config.js?

[Kristinita]

Are there any chances that this feature will be implemented to HTMLHint?

Thanks.