Further improve logging (at some point maybe)

[teutoburg]

Not any priority, just to not forget about it...

As the name suggests, skycalc_ipy is intended to (also) be used from interactive IPython sessions. In this use case, it is unlikely that logging will be configured externally, but we might still want to give the user an easy option to receive logging messages. For the future, I thus propose to:

• Add a "verbose" option to SkyCalc
  This would internally configure a console handler for our loggers. We might want to set this to True by default.
• Allow different levels of verbosity
• Add more (info, debug) logging for normal operation

And eventually maybe

• Split the interface for interactive use and internal use
  Maybe this is already done with ui.get_almanac_data() in some places? Anyway, if the function/class used when skycalc_ipy is imported as a library in the background (e.g. in ScopeSim) is different from the one used interactively, the verbosity options discussed above might be easier to configure.

Originally posted by @teutoburg in #42 (comment)