E2EE for embeded mode

[SimonBrandner]

Based on #1348
Requires matrix-org/matrix-js-sdk#3667

[codecov-commenter]

Codecov Report

Patch coverage: 28.57% and project coverage change: +0.21% 🎉

Comparison is base (9efb159) 26.23% compared to head (28035b5) 26.44%.

Additional details and impacted files

@@             Coverage Diff             @@
##           livekit    #1350      +/-   ##
===========================================
+ Coverage    26.23%   26.44%   +0.21%     
===========================================
  Files           50       50              
  Lines         2028     2042      +14     
  Branches       337      341       +4     
===========================================
+ Hits           532      540       +8     
- Misses        1459     1464       +5     
- Partials        37       38       +1     

Flag	Coverage Δ
unittests	26.44% <28.57%> (+0.21%)	⬆️

Flags with carried forward coverage won't be shown. Click here to find out more.

Files Changed	Coverage Δ
src/UrlParams.ts	91.42% <ø> (+14.28%)	⬆️
src/home/CallList.tsx	100.00% <ø> (ø)
src/widget.ts	18.91% <0.00%> (-0.53%)	⬇️
src/e2ee/e2eeHooks.ts	27.65% <28.57%> (ø)
src/settings/useSetting.ts	52.27% <40.00%> (-2.49%)	⬇️

☔ View full report in Codecov by Sentry.
📢 Have feedback on the report? Share it here.

[dbkr]

I've created #1772 to re-apply the changes here (or most of them) as this is super conflicty now.