Add attach/detach keybinds and allow editing attached objects directly

[mharis001]

When merged this pull request will:

• Add "Attach Objects" and "Detach Objects" keybinds to attach/detach multiple objects at a time
• Allow editing attached objects directly
  • Previously, attached objects would snap back to their original position when edited through Zeus
  • Now, we manually re-attach them based on their new relative position to the parent object
• Move all attached objects handling to new attached_objects component

[Kexanone]

Any reason you chose Alt over Ctrl for the default keybind?

[mharis001]

Do not remember why. Would Ctrl be a better default?

[Kexanone]

I messed up before... I meant to replace Shift with Ctrl, since I find Ctrl+Alt+Key a more natural choice than Shift+Alt+Key, but it's probably more a matter of personal preference.

[mharis001]

Changed to CTRL + SHIFT + _. Feels like the most natural to use.

[Kexanone]

Ctrl+Shift is actually even better. Anyway ppl can adjust it to whatever they want, so no big deal in the first place.