Allow replacing close event to custom commands

[xzbdmw]

Is your feature request related to a problem? Please describe. In neovim, I use floating terminal to open lazygit, and it makes perfect sense if close event is translated into a custom command such as `nvim --remote --send-keys "<Cmd>close"' which hide the terminal window, so next time lazygit does not need to restart.

Describe the solution you'd like Adds a new keymap to trigger custom commands everytime layzgit is about to close itself, and keep a keymap to actually close lazygit when needed.

Describe alternatives you've considered I can bind a key in neovim to toggle terminal, but it is not intuitive to use because return at top level is very useful but can not be achieved in neovim side(I'm so used to press esc so many time I just unexpected close lazygit). Additional context Add any other context or screenshots about the feature request here.