Add tmux package and common dotfiles deployment

dotfiles/common/.tmux/plugins/tmux-continuum/docs/continuum_status.md

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+## Continuum status in tmux status line
+
+There is an option to display current status of tmux continuum in tmux status
+line. This is done via `#{continuum_status}` interpolation and it works with
+both `status-right` and `status-left` tmux native options.
+
+Example usage:
+
+    set -g status-right 'Continuum status: #{continuum_status}'
+
+When running, `#{continuum_status}` will show continuum save interval:
+
+    Continuum status: 15
+
+or if continuous saving is disabled:
+
+    Continuum status: off