Separate user output from logging output

User output is output that arises from regular usage of the program, destined for the end user. By default goes to stdout. The application developer has full control over it, since imported libraries should not print. It is a big plus if it is pleasing to the eye.

⠼ 🔨 Building Kontrol project 🔨

Logging output is for tracking certain internal events of execution for monitoring or debugging. By default goes to stderr*. It is not trivial to fully control this type of output, since dependencies also write their own log messages (as they should). Should be easy to process automatically, so the more rigid the format, the better.

INFO 2024-06-25 23:45:35,004 kontrol.kompile - Copying requires path: test/kontrol/lido-lemmas.k -> out/kompiled/requires/lido-lemmas.k

*Logging to a file should be an option. Also, once these two types of output are separate, logging can go to a file by default to not confuse the regular user with this information.

Related: https://docs.python.org/3/howto/logging.html#when-to-use-logging

The issue names no files, tests, or entry points. Start by locating where Kontrol produces user-facing output and where logging is configured; done means regular output and logging use separate streams, with logging format and file output behaving as described.