increase the default log level

The vast majority of spans are at the info level, so increasing the log
level to info will greatly increase the amount of (useful!) inforamtion
included in the logs.

However, `ruma_state_res` generates a substantial amount of logs, so
that one gets to stay fixed at `warn` for now.

src/config.rs

@@ -210,7 +210,7 @@ fn default_trusted_servers() -> Vec<OwnedServerName> {
 }
 
 fn default_log() -> EnvFilterClone {
-    "warn,state_res=warn,_=off"
+    "info,ruma_state_res=warn"
         .parse()
         .expect("hardcoded env filter should be valid")
 }