Make it possible to reorder sessions by pressing Ctrl+Shift+PageUp like in GNOME Terminal

[TylerRick]

Coming from gnome-terminal, I was pleased that Ctrl+PageUp work as I am used to... Would be nice if I could reorder the sessions (to me, they're "tabs") as well, with Ctrl+Shift+PageUp/PageDown. This is the same shortcut for reordering tabs used by gnome-terminal, chromium-browser, and possibly others...

Of course, this would make a bit more sense if sessions were actually tabs — then you could actually see the tabs moving when you pressed the shortcut... So, since tabs are appear to be out (#114, #268), what visual feedback would we show the user? Perhaps open the sessions sidebar briefly to show the animation of sessions being moved and then hide it again after a second?

See also #264 (reordering with mouse)

[TylerRick]

As it is, if I want two sessions to be "next to" each other (so that I can switch between them quickly with Ctrl+PageUp/PageDown without having to travel through other sessions to get there) ... I have to very intentionally plan things out as I add new tabs... I can't put them in the desired order after the fact (unless I'm missing something)...

Only workaroud I've found so far is painful... drag a session(s) out of the window to detach it, create new sessions where you desire them to be attached, drag the detached sessions back to the placeholder session that is in the position you want it to be in (which I can't seem to do without creating a split), close the temporary placeholder session that the desired session is split with, and you end up with the session where you want it...!

[gnunn1]

I've added initial re-ordering of sessions via DND, I'll add support for doing the same via these shortcuts over the weekend.

[TylerRick]

I still don't see session reordering commands listed under Preferences > Shortcuts in Tilix 1.6.4.

Did shortcuts actually get added for this? I see it mentioned in https://github.com/gnunn1/tilix/releases/tag/1.5.8 but Ctrl-PageUp or Ctrl-PageDown (for me at least) are bound to Switch to next/previous session (as they should be).

and Ctrl+Shift+PageUp/PageDown (the shortcuts I would suggest for re-ordering) don't appear to be bound to anything.