[FEATURE] Ability to copy an entire project

**Is your feature request related to a problem? Please describe.**
My preferred method of managing lifecycle with dev, test, and prod environments is to have an entirely separate project for each of the 3. Currently, there is no way to copy an entire project, only to make a copy of a workflow in one project and then move it to another project.

**Describe the solution you'd like**
I'd like to be able to select elements across a project that should be copied to another project, including resources, files, and variables. This will significantly simplify the process of promoting changes from one project to another.

**Do you have a workaround?**
Yes, I can duplicate workflows in one project, move the duplicates to another project, delete the previous versions in the target project (if any), rename the moved workflows, and then manually verify that all variables exist and are set correctly for the target project, and then manually make sure that any necessary files are present in the target project's file store.

**Comparable features in other tools?**
No idea.

**Additional context**
Add any other context or screenshots about the feature request here.