feat(grfn/system): Resuscitate roswell

Resuscitate the configuration for roswell, the semi-portable
configuration I use for ec2 development boxes. Lots of the changes here
are trying to get Tramp working.

Change-Id: I2dc2fd1d9aa76e145fa3f3f847af761cb652ab47
Reviewed-on: https://cl.tvl.fyi/c/depot/+/5798
Reviewed-by: grfn <grfn@gws.fyi>
Autosubmit: grfn <grfn@gws.fyi>
Tested-by: BuildkiteCI

users/grfn/system/home/modules/pure.zsh-theme

@@ -92,6 +92,10 @@ prompt_pure_nix_info() {
 }
 
 prompt_pure_precmd() {
+	if [[ "$TERM" == "dumb" ]]; then
+		return
+	fi
+
 	# shows the full path in the title
 	print -Pn '\e]0;%~\a'