Open file selections and metadata in Vol-E v2

[frasercl]

Context

For a while, we've wanted a way to send more data to an opened Vol-E window than could practically fit in URL query parameters — namely, large selections of images and image metadata. Previous passes at this include #516, which got caught up in arcane browser security policies; and #566, which requires an intermediate server, and targets CFE rather than Vol-E. The implementation in this PR happens entirely locally, appears unlikely to run afoul of any cross-origin isolation, and has the convenient bonus of being backwards-compatible with versions of Vol-E that aren't expecting the extra protocol.

Changes

Here's how it works:

• The new openInVole handler always includes something in the url query param of the Vol-E URL it opens, which ensures Vol-E will always show something even if one of the steps below fails.
• ...but it also adds new query params: storageid uniquely identifies the message BFF will send to Vol-E, and msgorigin is the origin of the opening BFF window (the slice of the URL from the beginning through the port, i.e. https://bff.allencell.org), which helps with security.
• On load, Vol-E recognizes that those params are present and uses postMessage to send the value of storageid back to BFF, indicating that it's ready to receive the message content.
• Once BFF receives that message back from Vol-E, it postMessages back the extra data.

allen-cell-animated/vole-app#467 is the counterpart PR on the Vol-E side. It gets into the details of how Vol-E handles the received message.

Testing

With BFF on this branch...

• Make a large selection of image files and choose "Open in Vol-E." Expectation: only the "focused" image should open in Vol-E. msgorigin and storageid will be in the URL but unused.
• Select a small number of image files (~3) and choose "Open in Vol-E". Expectation: this branch is willing to put small multi-scene collections in the URL, so all these images should open at once (the "Scene" slider will be visible in Vol-E's "Clipping" panel). msgorigin and storageid should still be there to send image metadata.
• Change VOLE_BASE_URL to http://localhost:9020/viewer, and start Vol-E locally on the branch feature/receive-from-bff. Make a large selection of image files and choose "Open in Vol-E." Expectation: subject to the caveats described in Receive multiscenes and metadata from BFF allen-cell-animated/vole-app#467, Vol-E will open the whole image collection, starting on the image that was "focused" in BFF, and data from other columns in BFF will appear in Vol-E's "Metadata" panel.

[frasercl]

Didn't end up breaking out a custom hook for this because:

1. It uses the tiny utility function getFileExtension and I didn't feel like copying it over.
2. More importantly, it uses openWindowWithMessage. Like I said in that function's docs, it may be useful for opening large collections of data in other apps, and I didn't want it isolated in another file just yet.
3. The implementation below is just on the edge of feeling okay to include inline, if openInCfe was long enough to break out.

Any of the above could fall the other way for someone else or change in the future though, so I also kept the comment.

[frasercl]

This was already present somewhere further down the dependency tree, so depending on it explicitly doesn't change much.