Chore: reformat all templates to 2 spaces

[lalver1]

Closes #2591

This PR:

• Sets the default number of spaces to 2 for html files
• Modifies the pre-commit config to run the djlint-reformat-django pre-commit job before linting
• Reformats all templates to 2 spaces (ran pre-commit run --all --all-files in the dev container)
• Adds node_modules/ to .gitignore

[github-actions]

Coverage report

This PR does not seem to contain any modification to coverable code.

[machikoyasuda]

Thank you for taking on this issue!

[machikoyasuda]

Starting my review on this.

[machikoyasuda]

Confirmed:

• When switching from Python file (spaces: 4) to an HTML file (spaces: 2), VS Code appropriately switches spaces setting.
• When creating a new HTML file, VS Code setting has the spaces set to 2.

[thekaveman]

Let's get it in!

[lalver1]

I made no changes except for rebasing this branch (git rebase main) to include the fix in #2629 and fix the merge conflict. Turns out that I didn't need to manually run pre-commit on benefits/eligibility/templates/eligibility/start--sbmtd-agency-card.html since the file automatically got formatted as part of the rebase.