Install VA-API-related packages by default

## Problem

Gstreamer cannot use VA-API by default to encode and decode media in Web, Videos, etc. by default. This is not ideal as load on CPU substantially increases when watching videos/ dealing with media, when users who come from other operating systems (like Windows and macOS) are used to the GPU doing the work by default.

## Proposal

Reference: https://wiki.archlinux.org/title/Hardware_video_acceleration
Check if hardware is compatible with VA-API (i.e. compatible Intel GPU)
Ask if user wants non-free software for video acceleration (e.g. `intel-media-va-driver` VS `intel-media-va-driver-non-free`), this option should also decide whether proprietary codecs (e.g. gstreamer1.0-plugins-bad) are installed
Install and configure gstreamer1.0-vaapi by default
Set the LIBVA_DRIVER_NAME environment variable to the correct one

(Further discussion necessary on when in the set-up process should the user be asked about this)

## Prior Art