Fallback to different servers in case matrix.org is down on first launch

[bxdxnn]

When the default matrix.org HS is down or blocked, it'll look like the app is broken when the user will try to register, leading to uninstalls.

As the common user wouldn't know/bother what is a "homeserver" and that you can change it when registering, It would help to at least provide a fallback to element.io in case matrix.org is down, and possibly other favored community servers in case there are some other outages (e.g. Cloudflare)

@mxandreas PTAL, and please let me know if this is not a priority right now (but the product/design decision is made), but outside contributions are welcome to implement it.

[mxandreas]

I think we have talked about showing users that there is an outage. element.io is not a public server where anyone can register, and I am not sure what other public servers could be recommended instead of matrix.org - that is very subjective.

[bxdxnn]

Yes, it's very subjective, but that's why a product decision is needed.
As a start, some reliable servers are listed on the matrix.org's website: https://matrix.org/ecosystem/hosting/

As an alternative, matrix.org may host some backup servers, but it will be expensive and that wouldn't fix the case when the server is blocked, e.g. in India.

P.S. a general issue is that we might also just choose a random server on launch so that matrix.org won't be so overloaded.