Make MergeWorkspacesWithLimits more suitable for general use

This commit modifies the MergeWorkspacesWithLimits algorithm to be usable
outside of the polaris scripts. The changes to the algorithm are as follows:

- Fixing the ADSValidator export to python.
- The Algorithm can now accept a group workspace, a multi-specta workspace, or a list of workspaces.
- The Algorithm can take an input use with MatchSpectra for if the scale or offset should be calculated

Re: #27445