Refactoring louloulibs and cmake

Use OBJECT libraries
Remove the louloulibs directory
Write FOUND variables in the cache

Remove all the libs that are now in louloulibs

Fix the systemd-conditional code

By using SYSTEMD_FOUND instead of SYSTEMDDAEMON_FOUND, where I forgot to
rename it…

Properly display [DEBUG] on debug lines, instead of [ERROR]

Use systemd-daemon logging prefix if available

Upgrade to C++14

Use the logger everywhere

Add a logger class