Update Goniometer initialisation

Goniometer initialisation is now done on a per-instrument basis. A sample goniometer can now have 1-3 axes (minimum 1, used to be fixed at 3) and a detector goniometer can have 1-2 axes (minimum 1, used to be fixed at 2). Crucially, the detector goniometer now has input parameters (angles) and is correctly initialised instead of the angle defaulting to zero. These changes are made with the aim of reducing HEIDI and POLI data, which will have a 2D detector with a single (gamma) goniometer axis.

• Reduce boilerplate by intialising sample and detector angles in Diffractometer.h
• Rename sampleStates and detectorStates to sampleAngles and detectorAngles to avoid confusing. No longer public.
• Add 2theta(gamma) and 2theta(nu) to reader parameters
• Remove unneed axes from BioDiff.yml. All instruments will require sample goniometer and 1 detector gonioimeter (even if the detector goniometer is fixed over a run)
• Set 2theta(gamma) and 2theta(nu) in the GUI when loading a data set
• Actually use AutoIndexerParamters::maxdim to filter out unreasonable solutions

Resolves #670 (closed), #671 (closed), #156 (closed), #643 (closed)