Refactoring louloulibs and cmake

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

Fix a bug in cut()

cut messages at 512 bytes, taking into account the UTF-8 codepoints

ref #3067

Refactor, test and improve the way we cut too-long messages for IRC

Introduce the configure ad-hoc command on irc servers

Provides two options for now, and they have no effect yet