Instead of a user config that always shows a selection on focus, the
focused main view starts without a selection (matching master). Pressing
<space> shows a selection in the middle of the view (no scrolling);
pressing <esc> hides it again before falling through to exiting the view.
I copied all files except dot files (.github and .gitignore), the _examples
folder, and go.mod/go.sum.
At some point we may want to copy the files back to the gocui repo when other
clients (e.g. lazydocker) want to use the newer versions of them.
In this commit this is only possible by pressing '0' in a side panel; we'll add
mouse clicking later in the branch.
Also, you can't really do anything in the focused view except press escape to
leave it again. We'll add some more functionality in a following commit.