Galen consultations prj 27 add ref number wkflw step

[whatisgalen]

Types of changes

• Bugfix (non-breaking change which fixes an issue)
• [x ] New feature (non-breaking change which adds functionality)
• Breaking change (fix or feature that would cause existing functionality to not work as expected)

Description of Change

Adds a new step type for workflows allowing multiple tiles to be saved during that workflow step

Ticket Background

See PR in consultations-prj: archesproject/arches-her#54
Original ticket: archesproject/arches-her#27

Further comments

While the scope of the ticket did not explicitly state the need for a generic, multi-tile workflow step, using the mockups it was clear that this is what was required given that other steps would likely need to make use of handling multiple tiles.

[coveralls]

Coverage remained the same at ?% when pulling 4505603 on galen_consultations-prj_27_add_ref_number_wkflw_step into 09638f5 on master.

[whatisgalen]

this will probably throw a require.js error if it's merged without the companion branch: #4905

[robgaston]

@whatisgalen can you please remove the many _.DS_Store files added here? we don't want them in the repo and they make it more difficult to review the actual functional changes in this PR. Thanks!