Basic structure for ConvertToYSpace algorithm

Refs #8598
Refactoring to avoid code duplication.

* getComponentParameter is now only defined in ConvertToYSpace
* DetectorParams struct has moved to ConvertToYSpace
* Y calculation has moved to ConvertToYSpace

Refs #8598
Tidy up in ConvertToYSpace and implement exec test

Refs #8598
Set units on output workspace.

Refs #8598
Implement a profile function to fit a mass peak in Y-space.

Used in neutron compton scattering to Fit a spectrum using only the proton
peak.
Refs #8598
Start of NormaliseByPeakArea algorithm

Refs #8598
Refactor test helper to allow multiple spectra.

Refs #8598
Symmetrised output is correct for non-sum behaviour

Refs #8598
Implement summing behaviour in NormaliseByPeakArea.

Refs #8598
Merge branch 'feature/8598_convert_to_yspace' into develop