Pls merge

[Twig6943]

• Adds -lm Add math lib to extra libs #14
• Makes it use .config for files (this is required for it to work without root in some cases)
• Adds placeholder CONTRIBUTING & actions files

[normalUserKarn]

this is a necropost or something, but
rm -f ~/.config/speedhack/speedhack_{pipe,log}
should probably be replaced with
rm -f ~/.config/{speedhack_pipe,speedhack/speedhack_log}
to function as intended

[evg-zhabotinsky]

Sorry for the wait, this PR slipped my attention.

• What is -lm for? I distinctly remember getting rid of the flag to avoid a potential extra dependency for portable builds. The current "release" binaries only depends on libc.
• Moving from /tmp to ~ is indeed a good idea for multi-user systems, in case there are stale files from other users, but I think ~/.cache/libspeedhack/ would be a better location, it is the closest per-user equivalent to /tmp.

[Twig6943]

just nvm this pr (this thing is kinda useless since it needs to be rewritten