Logs

[Halbaroth]

This PR starts to use logs to print debug messages. I tried to keep it as reasonable as possible, so I didn't change all the printers.

• Every named modules and functions are located in a new module Self. I created this module because we share these named locations between printers, timers and the profiling module;
• Each named modules expose a Logs source (see Self.get_source);
• The CLI option --dd changes the level of these sources;
• I use the tag feature of Logs to print function names;
• I clean and use Logs to print debug messages in Shostak, Satml, Satml_frontend and the enum theory;
• The new Logs reporter Printer.reporter chooses the appropriate output according to the source.