[Feature Request] Add IPC or CLI option to open new windows from existing rio instance

[sga-13]

Description:- please add a cli option or some IPC interface to open new window from existing instance. Currently rio supports opening new windows from a existing window through keybindings or decorations, which results in multiple windows, but only 1 instance, and hence reduced memory usage. If a cli (something like foot --server and footclient) or a ipc interface (like alacritty msg create-window, if you have enabled ipc in alacritty config) is added, then the new window can be opened outside rio. My usual way to use terminals is having multiple windows on different desktops opened through my launcher, and if they can share the base rio instance, it will lead to reduced memory usage.