Add container subtraction tab to indirect

[ElliotAOram]

Fixes #13110

The new ContainerSubtraction tab is now in the Indirect Corrections tab.

To Test

• Open the ContainerSubtraction tab (Interfaces > Indirect > Corrections > ContainerSubtraction)
• Select a suitable Sample File and matching Container file.
• Optionally Scale the container
• Run the Subtraction
• Several features need to be checked to ensure that the new tab functions correctly:
  • The plot options plot the correct things
  • The plot preview displays correct and reasonable data
    • This can be checked against the ApplyPaalmanPings tab (without using corrections only can). The can subtraction will be removed from the ApplyPaalmanPings tab at a later date.
  • The relevant files appear in the ADS
    • Original files
    • Wavelength converted versions of the originals (if they were not in wavelength originally)
    • The container subtraction

This has should now feature in the Indirect_Corrections.rst

ToDo:

• update release notes (http://www.mantidproject.org/Release_Notes_3_5_Indirect_Inelastic#New_features)

[raquelalvarezbanos]

Code and documentation look good.

I have checked that:

• Plot options and Preview plot produce the expected plots
• Relevant files appear in ADS
• "Scale Can by factor" works correctly

I've only noticed an issue when the input workspaces have different binning. In this case, when running the container subtraction, I get the following error:

Error in execution of algorithm Minus:
X arrays must match when performing this operation on a 2D workspaces.
Error in execution of algorithm ApplyPaalmanPingsCorrection
X arrays must match when performing this operation on a 2D workspaces.
...

@ElliotAOram Not sure how frequent this situation is (sample and container with different binning), so let me know if you would like to solve this in a separate issue and I'll merge this branch.

[ElliotAOram]

Thanks @raquelalvarezbanos I think it's fairly uncommon so it should be fine to solve separately.