Adapt PyConf API to snake_case convention
Towards a more consistent API that uses snake_case notation. As per our discussions @apearce and @rmatev.
Relates to DPA's https://gitlab.cern.ch/lhcb-dpa/project/-/issues/89 on consistent coding conventions across the whole software stack.
Required for Rec!2354 (merged), Moore!755 (merged), MooreAnalysis!28 (merged) and DaVinci!507 (merged).
Edited by Alex Pearce