refactor(sdk): Split supported versions and well-known cache

[zecakeh]

The supported versions are necessary for querying almost all endpoints, but after homeserver auto-discovery the well-known info is only,necessary to get the MatrixRTC foci advertised by the homeserver. So it shouldn't be necessary to always request both at the same time.

Besides:

• Not all clients support MatrixRTC, so they don't need the well-known info.
• The well-known info is only supposed to be used for homeserver auto-discovery before login. In fact, the MatrixRTC MSC was changed to use a new endpoint for this: https://github.com/matrix-org/matrix-spec-proposals/blob/680ef7dd65bbfbc275cc3177f36286e94c021fa9/proposals/4143-matrix-rtc.md?plain=1#L671-L724.
• We don't have access to the server name after restoring the Client, so the well-known lookup is more likely to fail as seen in Prevent HomeserverConfig::discover from performing the discover request if previous server info exists #5877.

This can be reviewed commit by commit, although most of the change happens in one of them.

[codecov]

Codecov Report

❌ Patch coverage is 86.19403% with 37 lines in your changes missing coverage. Please review.
✅ Project coverage is 88.65%. Comparing base (73449f4) to head (a6ade9c).
✅ All tests successful. No failed tests found.

Files with missing lines	Patch %	Lines
crates/matrix-sdk/src/client/mod.rs	84.43%	12 Missing and 14 partials ⚠️
...tes/matrix-sdk-base/src/store/integration_tests.rs	86.00%	0 Missing and 7 partials ⚠️
crates/matrix-sdk-base/src/store/traits.rs	94.11%	0 Missing and 2 partials ⚠️
crates/matrix-sdk-sqlite/src/state_store.rs	50.00%	0 Missing and 2 partials ⚠️

Additional details and impacted files

@@            Coverage Diff             @@
##             main    #5910      +/-   ##
==========================================
- Coverage   88.66%   88.65%   -0.02%     
==========================================
  Files         362      363       +1     
  Lines      104399   104490      +91     
  Branches   104399   104490      +91     
==========================================
+ Hits        92569    92637      +68     
- Misses       7499     7507       +8     
- Partials     4331     4346      +15     

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[codspeed-hq]

CodSpeed Performance Report

Merging #5910 will not alter performance

_{Comparing zecakeh:split-well-known (a6ade9c) with main (73449f4)}

Summary

✅ 50 untouched