This moves adding to lists and getting long values into resuable functions.
It also fixes a couple other issues in the process:
1. Logging now goes to the error channel and is labelled
2. >Max length lines are properly handled, although this should never happen since inih has a 200 limit
Checks for a gamemode.ini in /usr/share/gamemode/ (or in the cwd for debugging)
Currently allows for blacklisting and whitelisting clients based on rudimentary needle-haystack executable name checks
See the example/gamemode.ini file for expected syntax
Using the BSD licensed inih library (with additional meson.build file)
