Add status and management UI for the event indexer

[poljar]

This PR implements some initial UI for our event indexer.
Things that are configurable/shown:

• Enable/disable the crawler
• Setting controlling how fast the room history is being downloaded.
• See how much disk usage the event index is consuming
• See if the crawler is currently downloading room history.

Some more things we might want:

• Configure the event index to crawl non-encrypted rooms as well.
• Trigger a manual re-crawl of a room
• A decoration showing the current shown room is currently being crawled.
• Language settings (some discussion for this can be found already here Language-specific tokenisers seem hard to use properly seshat#7)

As for configuring non-encrypted rooms we should consider if we want to allow users to index any type of room or limit it to non-public rooms or DMs only.

Rendered:

The settings have been crammed into the preferences tab of the user settings. This is most likely the completely wrong place to put them since we already have quite a large number of settings there.

A new tab for the settings was also considered but we may have enough tabs as well.

Please note that this PR depends on changes in Riot-web as well (element-hq/element-web#11529)

Fixes element-hq/element-web#11984

[ara4n]

From a high level functionality perspective this looks great. I think we can afford to expose a little more information to the user to give them more visibility and a sense of control though (at least until we are confident this works seamlessly).

• s/Enable message downloading/Download and index encrypted messages/
• The number of indexed messages (570KB in 125,432 messages over 129 rooms; 248KB of index)
• Listing the names of the rooms currently being indexed
• Delete cache button

In terms of where it should sit in the UI - I'd have expected it to be in Security & Privacy alongside the rest of the E2E settings.

@nadonomy: can you provide a design for this please?

[nadonomy]

@poljar for when you're back after Christmas/New Years I've added a design proposal for the seshat UI here:

https://www.figma.com/file/wwqBo5oAFfk8XKmtd2YaIs/Cross-signing?node-id=2011%3A497

Let me know when you're back online on Matrix and we can iterate on some of the details. From the requirements I could gather from this issue, there's a few things that would be good to discuss:

• Until we're clear of cross-signing dev, Settings in /develop doesn't represent the designs here, so we should quickly discuss where to place this within the 'Security & Privacy' tab in Settings in the meanwhile
• I'm not sure that users have a good expectation of what a [Delete cache] button would actually do— e.g. would this automatically start downloading & unencrypting messages again? Or would that be user initiated? So I think it makes more sense to keep the interaction to [Disable] & [Enable] the feature, where doing so would clear the cache.
• I'm not convinced of the utility of listing the names of the rooms messages are being fetched from; as the user can't manage any of it and it's problematic to scale if e.g. the user is in 1000 encrypted rooms.
• Are we implementing this on iOS/Android?

[poljar]

Until we're clear of cross-signing dev, Settings in /develop doesn't represent the designs here, so we should quickly discuss where to place this within the 'Security & Privacy' tab in Settings in the meanwhile

I guess bellow the key backup section seems sensible?

I'm not sure that users have a good expectation of what a [Delete cache] button would actually do— e.g. would this automatically start downloading & unencrypting messages again? Or would that be user initiated? So I think it makes more sense to keep the interaction to [Disable] & [Enable] the feature, where doing so would clear the cache.

As it is, it would restart the download. Agree a Disable/Enable could be enough.

I'm not convinced of the utility of listing the names of the rooms messages are being fetched from; as the user can't manage any of it and it's problematic to scale if e.g. the user is in 1000 encrypted rooms.

Agree, a summary should be enough, but some type of marker could be nice for when a user looks at a specific room. Just some visual hint if messages are being downloaded or not.

Are we implementing this on iOS/Android?

Eventually, yes. No progress as of yet on that side though.

[poljar]

Some progress here, refactored the main UI, moved it into the security tab of the settings and moved it into a modal.

I force pushed this after i locally rebased onto develop since the original PR was done on the old build system.

The disabling/enabling isn't yet hooked up.

Looks like this now:

[jryans]

We're nearly there, just a few more things to tweak!

[poljar]

Updated now to have a red transparent cancel button on the disable dialog.

I left the border around the button since it seemed a bit weird not having it there. The colors aren't the transparent ones like in the figma but I assume we want to switch those around all at once and be consistent for now.

Updated screenshots follow:

[jryans]

Looks great overall! Feel free to adjust the links as mentioned and land; no need for another review.

Thanks for working on this! 😁

[jryans]

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