Update installation docs #18
Description
The install section of the docs is pretty out of date:
https://github.com/guyfawcus/ArchMap/blob/master/docs/installation/index.rst#install
- Update requirements
- Add links to requirements
- Talk about installation from PyPi
- Talk more about installation from the AUR
- Add install section of https://github.com/guyfawcus/ArchMap/blob/master/systemd/README.md#installation
ArchWomen already have a pretty good write up on installation, It'd be a good place to get some pointers.