This change adds [LeftHook](https://lefthook.dev/) as a GitHub hook management tool alongside [MegaLinter](https://megalinter.io/) to lint all relevant files within the repository.
For users that don't end up installing LeftHook for pre-commit hooks, megalinter picks up the necessary formatting changes and reports them.
* feat: add lefthook, megalinter and update editorconfig
* fix: lint commit ordering
* refactor: adjust megalinter reporters
* refactor: adjust description for cache domains
* refactor: single - for passing options
* refactor: add repo-specific fmt in megalinter pre-commands too
The domain in question is already covered by a wildcard defined further in the list. In AdGuard Home this was causing said domain to have a round-robin DNS entry with the same IP twice.
This change addresses some general housecleaning for CDN hosts:
* Removing all hosts that do not resolve
* Only including the Steam CDN trigger address
