Support deep linking by page and/or component

[shawnbot]

This PR addresses FM-22 by adding support for the following form options (the second argument to Formio.createForm()):

• page takes either a 1-based index or a component key and attempts to set the current page of the form accordingly.
• focus takes a component key and attempts to give it focus.

There are a couple of extra considerations to make these work for cases that formio.js doesn't handle natively:

• If page key resolves to something other than a page component it gives it focus instead, which sets the page automatically. (This is easier than attempting to figure out which page contains the component)
• If the focus key resolves to a page component we route to it with form.setPage(index) instead. (Page components can't receive focus in formio.js)

I think there's value in having them separate, but I'm also willing to be convinced otherwise and just have a single codepath for "focusing" either a specific component or page.

Examples

• /examples/review/?page=2 displays the second page (via the query string)
• /examples/review/?focus=age focuses the age input
• /api/preview?options={"page":2} passes the page option to the feedback form preview
• /api/preview?source=https://sfds.form.io/testprophexpansion&options={"page":5}) skips to page 5 of the Prop H expansion form preview

In order to make this work on sf.gov proper (later, I think, since this is currently only something we need for testing), we'll need to handle parsing either the query string or hash and merging (w/validation!) those options into the ones that we pass the form here.

[github-actions[bot]]

Size Change: +277 B (0%)

Total Size: 88.6 kB

Filename	Size	Change
dist/formio-sfds.css	14 kB	-25 B (0%)
dist/formio-sfds.standalone.js	68.2 kB	+302 B (0%)

ℹ️ View Unchanged

| Filename | Size | | :--- | :---: | | `dist/portal.js` | 6.37 kB |

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[shawnbot]

Heads up to @hshaosf @nlsfds: this will be going out in the next release so you should be able to link to pages and/or components in form previews, but not (yet) on sf.gov.