Try to set canonical room alias on room creation.

Closes #123

See merge request famedly/conduit!154

The spec does not require servers to apply a room canonical alias event upon room creation (yet).
Still, synapse does that, since users can set their desired alias in Elements room creation dialog.
With this commit, conduit also sets that alias if it is a valid one.

This closes https://gitlab.com/famedly/conduit/-/issues/123

Bump version of alpine docker image to 3.14

See merge request famedly/conduit!150

Set nicer displayname

See merge request famedly/conduit!149

Add support for a minimal `r0/account/3pid`.

See merge request famedly/conduit!151

improvement: try to load missing prev events

See merge request famedly/conduit!152

fix: handle bad events in db better

See merge request famedly/conduit!148

Support creating rooms with a version

See merge request famedly/conduit!147

improvement: longer timeout, more descriptive errors

See merge request famedly/conduit!146

Sqlitefixes

See merge request famedly/conduit!144