refs #8644. New indexing workflow algorithm
refs #8644. Move to command based design.
refs #8644. Bring in other command types.

One issue yet to resolve is that we must keep the order of the operations the same as has been provided in the parameter arguments.
refs #8644. Do operations in order correct order.
refs #8644. Fix tests now that isValid is used.
refs #8644. Extract to method for interpreter steps.
refs #8644. Extend tests and add documentation.
refs #8644. Fix compiler warnings.
refs #8644. Add when spectra are not neighbours.
Merge remote-tracking branch 'origin/feature/8644_workspace_index_operations'