CreateGroupingWorkspace improvements

[Peter Peterson]

A few things:

1. Add a validateInputs() to check that the instrument isn't specified multiple ways and the Grouping isn't specified multiple ways.
2. Add OldCalFilename input to the "Specify Groupings" part of the gui.
3. Allow user to specify a grouping file rather than a cal file to load from. This is linked to #8046 implementing the underlying work.
4. If a pixel is not specified in any of the options for "GroupNames", then set its output group to zero.
5. Add a new bit of syntax to "GroupNames" where if a colon ':' exists in the string it is used as the delimiter between elements within a group, and other delimiters used to separate the strings between the groups.

[Nick Draper]

Bulk move to assigned at the introduction of the triage step

[Stuart Campbell]

This ticket has been transferred to github issue ​8892