[os_setup] complete refactor & rewrite

SUMMARY

os_setup/* scripts are disjointed & outdated -- they also both essentially do the same thing -- and it is foolish to operate under the assumption that Debian 11 is the only operating system.

Tentative Roadmap

1. refactor into os_setup/{{os_name}}/*.sh to allow for support of multiple OSes and multiple setups within each OS
2. merge os_setup/deb11_base.sh and os_setup/deb11_nonfree.sh while cleaning them up; in other words, rewrite this into a new script
3. determine if any script parts can be generalized across multiple operating systems, and if so, create folder for this (os_setup/helper/ or something) and use them.
4. add more OS support
5. ???
6. No Profit

Contributing

if you want to help, please do! just fork the repo & get at it, then PR! feel free to contact me (see my profile for various contact methods) if I do not respond in a timely manner to a PR -- but I probably will.