Add Client Well-Known docs.

[pixlwave]

Following on from element-hq/element-ios#7685, this PR adds documentation for all of the VectorWellKnown types handled in EI.

[Johennes]

If you have 2 minutes to add the web values from my comments, that'd be great. But otherwise looks amazing IMO. Thanks for doing this!

[pixlwave]

@Johennes nice, updated with the feedback. Let's see if we can get feedback for Android too before merging.

[bmarty]

Thanks for adding this doc!

I have added comments about what is supported on EA.

EA also supports "m.tile_server"."map_style_url", which is not documented yet, if I am not mistaken.

Code (model) on EA: https://github.com/vector-im/element-android/blob/main/vector/src/main/java/im/vector/app/features/raw/wellknown/ElementWellKnown.kt#L23

[pixlwave]

Super, thanks @bmarty, updated with your feedback. For the tile server, I think the documentation within the MSC should probably suffice? https://github.com/matrix-org/matrix-spec-proposals/blob/matthew/location/proposals/3488-location.md#well-known-configuration

[bmarty]

For the tile server, I think the documentation within the MSC should probably suffice? https://github.com/matrix-org/matrix-spec-proposals/blob/matthew/location/proposals/3488-location.md#well-known-configuration

I was not sure if the idea of this doc was to centralize all the possible configurations for the .well-known file, that Element clients may understand. If this is the case, I would add a paragraph about map tiler, which can eventually contain a link to the MSC.

Element iOS does not seems to support the location configuration, that's why I though this was forgotten.

[pixlwave]

Ah, EI does support the location configuration but its all defined in the SDK, so in the app it is handled in the configuration builder alongside the use of the VectorWellKnown models.

My original intent of this doc was to a place to capture Element specific configuration options that aren't documented anywhere outside of the code. But I can see where you're coming from, as EI also supports the device dehydration MSC in the well-known too. Maybe the best thing here would be to link to the respective parsers for each platform so its easy to find the implementations for the spec/msc documented support too?

We can do that in a follow-up though, for now I'm going to merge this PR.