Sg 1235 form layout update

[aekong]

updates the form layout and navigation, related to https://sfgovdt.jira.com/browse/SG-1235

also allows preview to proxy any url (to allow previews from multidev envs on pantheon)

[vercel[bot]]

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🔍 Inspect: https://vercel.com/sfds/formio-sfds/5sw7pm26o
✅ Preview: https://formio-sfds-git-sg-1235-form-layout-update.sfds.vercel.app

[github-actions[bot]]

Size Change: +2.13 kB (+2%)

Total Size: 90 kB

Filename	Size	Change
dist/formio-sfds.css	14.3 kB	+280 B (+2%)
dist/formio-sfds.standalone.js	70 kB	+1.85 kB (+3%)

ℹ️ View Unchanged

| Filename | Size | Change | | :--- | :---: | :---: | | `dist/common.css` | 332 B | 0 B | | `dist/portal.js` | 5.36 kB | 0 B |

_{compressed-size-action}

[aekong]

thanks for the review! applied the suggestions for linting errors, will address the other things soon. And yeah, let's sync up on this, I'll set up some time for us

[aekong]

i think that dangling line is because i didn't account for the last nav item 🤦 . should be fixed with this: https://github.com/SFDigitalServices/formio-sfds/pull/149/files#diff-e3adbf2b5c8bb0b30621685b9324d6588b681898cb332272c0a4ae3f910bdb03R62

looks ok now: https://formio-sfds-git-sg-1235-form-layout-update.sfds.vercel.app/examples/review