Use MxcUri instead of String for media URLs.
Fix wrong MXC URIs in tests.
Remove method parse_mxc no longer useful.
Apply new non-exhaustive types: CrossSigningKey, OneTimeKey and SignedKey.
Apply endpoint name change: send_state_event_for_key to send_state_event
This sets the default
* connection timeout to 5s
* request timeout to 10s
* request timeout for syncs to the sync timeout + 10s
* request timeout for uploads to be based on 1Mbps upload
speed expectations
While it's generally useful to watch what the sdk is sending
out during development using mitmproxy, users of the sdk might
wonder why the example doesn't connect.
Remove the proxy usage until we add a cli parser which can enable proxy
support with a command line switch.
