Add tmux session management plugin

Added tmux-resurrect plugin. This allows easy persisting of sessions
through a server shutdown. To save a session, use
<leader><c-s>, to restore it <leader><c-r>.

.config/tmux/tmux.conf

@@ -54,6 +54,7 @@ set -g @plugin 'tmux-plugins/tmux-yank'
 set -g @plugin 'tmux-plugins/tmux-prefix-highlight'
 set -g @plugin 'Morantron/tmux-fingers'
 set -g @plugin 'christoomey/vim-tmux-navigator'
+set -g @plugin 'tmux-plugins/tmux-resurrect'
 
 run -b "${TMUX_PLUGIN_MANAGER_PATH}/tpm/tpm"