feat: move more linters from SuperLinter to pre-commit

[tk-woven]

Description

This is toward #114 . This moves more linting from SuperLinter to pre-commit. In particular, it moves

• check-json
• gitleaks
• htmlhint
• shellcheck
• shfmt

For gitleaks, we have to use a Docker-wrapped hook ID to avoid having our end-users manually install the gitleaks tool themselves. Also, SuperLinter suggests that it runs shfmt but is not entirely clear about it (since its configuration is for shellcheck).

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This change is 

[tk-woven]

Also, note that we use check-json in place of SuperLinter's eslint because eslint is not automatically installed. We'd have to ask end-users to manually install it (if outside of Docker), which I find annoying.

[tk-woven]

Ah, also note that DGP has no checked-in shell files from what I can tell. However, to preserve SuperLinter coverage, we add shell-checking hooks since SuperLinter would provide them to us the moment we (maybe) introduce shell files.