chore(tmux): use XDG_CONFIG_HOME to setup plugins

Also update tmux config to reflect this change, and mount a plugin dir.

config/tmux/tmux.conf

@@ -89,11 +89,11 @@ set-option -g display-panes-colour colour166 #orange
 # clock
 set-window-option -g clock-mode-colour colour64 #green
 
+# buffer size
+set -g history-limit 50000
+
 # list plugins
 set -g @plugin 'tmux-plugins/tpm'
 set -g @plugin 'Morantron/tmux-fingers'
 set -g @plugin 'tmux-plugins/tmux-yank'
-run '~/.tmux/plugins/tpm/tpm'
-
-# buffer size
-set -g history-limit 50000
+run '~/.config/tmux/plugins/tpm/tpm'