Use spaceship operator to fix issue for multiple pressure/depth curves
It was not possible to show two pressure/drop curves at the same time. This was caused by inconsistent implementation of operator< and operator==. Implement operator <=> to simplify the code.
Move AppEnum init to RifDataSourceForRftPlt
Simplify constructors for RifDataSourceForRftPlt
Rename enum names in RifDataSourceForRftPlt::SourceType
Add missing pressureDepthData in RimDataSourceForRftPlt