Follow snake_case naming conventions rather than camelCase

I noticed that we're not really following what seems to be the preferred naming conventions for upgrade code, hence this MR to improve on that from the onset. This is just a few first changes to make sure everyone is happy - @pkoppenb and @dfazzini.

I'm profiting from the occasion to make the main configuration functions available from the top level, to run as gaudirun.py DaVinci:data rather than gaudirun.py DaVinci.ConfigurationUpgrade:data, as agreed.

Hopefully we can converge here and have it all merged for Monday for the hackathon.