Replace DoS indentation with spaces

Refs #9340
More Pylint fixes in DoS

Refs #9340
Set sample material for partial DoS workspaces

Refs #9340
Add options for cross section scaling and summing to DoS

Refs #9340
Added input validation

Refs #9340
Updated DensityOfStates doc tests

The addition of CheckSpectraMap should be temporary

Refs #9340
Fixed doc test, added more unit tests

Fixed fault where eigenvectors were not parsed when they were needed

Refs #9340
Keep conventional summed WS name

More logical and will fix system tests

Refs #9340
Allow selection of any scattering cross section

Refs #9340
Correct failing unit test

Refs #9340
Merge branch 'feature/9340_dos_scattering_cross_sections' into develop