Migrate the existing checker / suggester code to instead use the new validator framework. We need to add,

1. Add a custom validator to Translate extension for printf check - /%(\d+\$)?[sduf]/U
2. An insertable for - /%\d\$s/; eg: %1$s
3. An insertable and validator for - %Y-%m-%d. Must ensure that we use only %Y-%m-%d or valid date formats
4. An insertable (not enforced) for HTML tags. Noticed anchor, strong tags
5. Replace braceBalanceCheck with BraceBalanceValidator

We'll need to update the YAML configuration file located here - https://phabricator.wikimedia.org/diffusion/GTWN/browse/master/groups/

Documentation: https://www.mediawiki.org/wiki/Help:Extension:Translate/Validators
Example patch: https://gerrit.wikimedia.org/r/c/translatewiki/+/549930