Add logging and debug configuration

[agle]

We need some organised logging system, likely use https://github.com/dbuenzli/logs

This needs to be integrated with verbosity flags, as well as flags for setting debug levels.

• logging should have the ability to switch on logs in specific contexts; e.g. for specific analyses to make it easy to filter
• debug levels should be configurable to enable different assertions and potentially write debug info to files etc

It is important the logging system does not execute the printing/formatting code for disabled log levels.