Update due date information to say Tags instead of Groups

[SamGarza1]

Problem statement:

When viewing assignments with multiple due dates instructors see "Group" when a Tag is used with Assign To

Proposed solution:

Update the language to say Tag(s) instead of Group(s) 

User role(s):

admin, instructor, ta

[tle1]

This is an issue in other places as well.

Even though they are labeled groups/tags in the assign-to pull down, it is still easy to accidentally choose a group instead of a tag or vice versa -- (or a subsection since we may still need to end up making groups, tags and sections that all match in order to obtain the functionality we want) Especially when the group/section/tag list is long.

Maybe make a (colorblind friendly) background separating sections, tags and groups in the assign-to pulldown. (And everywhere else?)