[Modules] Implement COPY TO... and DUPLICATE for "External URL" and "Text Header" item types

[SandaZG]

Problem statement:

I cannot duplicate text header nor external URL items within a module, nor can I copy such items to another course.

Proposed solution:

Add "Copy to..." and "Duplicate" actions to Text Header and External URL items within a module. Please make the available actions uniformly available for all applicable types of items in a module. Thank you!

User role(s):

instructor