installation/env.sh: Roll back to previous distribution handling (i.e. before the Debian 10 problem).

- Move packages.sh to env.sh, modify the other files accordingly.
- Find git root in a simpler way.
- Add a shebang where appropriate.

- Support easy removing of the packages dependencies.
- Improve detection of the repository root.

Note: For now, this configure script is very basic and non-standard.

- Fix a bug: correct display while running initramfs.
- Add a model kernel command (which fixes the bug).

- Generate new keys.
Note: they were originally generated while the repository was public, so they could not be trusted.
- Move the keys in uefi-keys/keys/
- Move mkkeys.sh to make_keys.sh and update it accordingly.
- Update dracut.module/dracut.conf.in accordingly.

- Create the directory. Move the relevant files in it.
- Add a script to install the dependencies and a Debian package.

Add README.md and TODO.txt

dracut.module/: Choose the version of the module's main script (collect.sh) in the Makefile. Add several versions.

- Label the relevant root partition.
- Add variables for relevant disks and parititions.