[Enhancement]: Arch package manager and terminal emulators selection

### Problem / Motivation

This post is motivated by two different factors:
1. Wanting to change the default terminal currently does not change it for Arch-update. Having an automated process during installation would just make it so it does it for your Selection.
2. Seeing that we move to Shelly as a default package manager, it would definitely be nice to have an option to go back to Octopi on Install.

### Proposed Solution

My suggestion is to add an Arch package manager (Octopi, Shelly etc.) and Terminal Emulators (Ghostty, Alacritty etc.) to the Calamares Installation Selection. Just like we do have currently for DE and Bootloader.

If there is a terminal or package manager that CachyOS does not officially support it should also be labeled as such in the installer.

### Alternatives Considered

Doing it manually post-install, but feel like a new user would have issues with it.

### Additional Context

_No response_