Clean the source tree
There are source files everywhere: /src, /src/core, ...
The tarot.c implementation is under the tarot/ folder where tarot.h is, whereas all other modules are the opposite...
Make autoconf macros, so that configure.ac is not too cluttered...
Put all sources under src/libtarot so that we can merge tarot.
Why merge tarot? Because it is difficult for the CI: I cannot work on both a new version of the lib and a new version of the package, because the package depends on a released version of libtarot.