lots of misc connection refactoring / fixes:
* adds blocklogger as a way to writing logging information from the backend directly to the a terminal block
* use blocklogger in conncontroller
* use blocklogger in sshclient
* fix remote name in password prompt
* use sh -c to get around shell weirdness
* remove cmd.exe special cases
* use GetWatcher().GetFullConfig() rather than re-reading the config file
* change order of things we do when establishing a connection. ask for wsh up front. then do domain socket, then connserver
* reduce number of sessions required in the common case when wsh is already installed. running the connserver is now a "multi-command" which checks if it is installed, then asks for the version
* send jwt token over stdin instead of in initial command string
* fix focus bug for frontend conn modal
* track more information in connstatus
* simplify wshinstall function
* add nowshreason
* other misc cleanup
