[NEW FEATURE] Enhanced mouse support

[jolsen-mitsu]

Right now you can use the mouse to click on a pane to select it and click on a container pane column header to sort the containers by that column. Please enhance the mouse support to include the following functionality:

Option 1:
If the user clicks on a pane that is not currently selected, then focus should be given to the pane that was clicked on. If the pane the user clicked on is already in focus, then perform an action on the item within the pane that was clicked on. For example, if the container pane was selected and row for "container_abc" was selected/current container (with the white dot to the left of it) and I clicked on the row for "container_xyz" then "container_xyz" should become the selected container with the white dot next to it. Similarly, if the user clicks on "restart" in the container actions pane, then it should restart the selected container. Same for the other actions like "start", "stop", "delete", etc.

Option 2:
Same as above except do not require the pane to have focus first, just immediately action the item within the pane that was clicked on.

Other notes:
Bonus points if you add right-click support for context menus (tmux also supports this). Then you could right-click on a container row to get a popup menu for options that would act on that container, such as start, stop, restart, delete, exec, etc.

As a side note, when mouse mode is enabled, you can use the shift key modifier to temporarily allow text selection. This can save a user from continuously enabling and disabling mouse mode just to select and copy text.