Pages Editor: add Copy Page feature

[shaunanoordin]

PR Overview

Part of: Pages Editor MVP project and FEM Lab super-project Follows #7100 Staging branch URL: https://pr-7102.pfe-preview.zooniverse.org/lab/1982/workflows/editor/3711?env=staging

This PR adds the ability to copy Pages/Steps - and their related Tasks - via the "copy" button. This PR adds the ability to copy Pages/Steps - and their related Tasks - via the "copy" button.

Screenshot: the "copy" button is the "two pieces of paper" button at the top right.

• New Feature: Copy Page (aka Copy Step)
  • duplicating Page also duplicates its Tasks.
  • each copied Page and copied Task is INDEPENDENT of the original Page/original Task. This means you can edit/delete a copied Step or Task without affecting the original.
  • A copied Page is appended at the END of the sequence of Pages.

Testing

• Open the test workflow in the Pages Editor using the Staging Branch URL. (Or pick any workflow of your choice, really.)
• (If the workflow doesn't have any Tasks yet, create something, or use the "Quick Setup" option in the ?advanced=true panel)
• Click on the "copy button" for any page, say Page X (with Tasks X1 and X2).
• A copy of Page X should be created, let's call it Page Y (with Tasks Y1 and Y2).
• Try editing Page Y (e.g. adding or removing Tasks). The original Page X should remain unchanged.
  • try vice versa
• Try editing Task Y1. The original Task X1 should remain unchanged.
  • try vice versa
• Try deleting Page Y.

Status

Ready for review. 👍 👍

Requires 7100 to be merged first before this can be merged. Requires 7100 to be merged first before this can be merged.

[coveralls]

coverage: 56.991%. remained the same when pulling 0c1497370e7cb9b08929b77d36c89abb624f116d on pages-editor-pt24 into d5416cbb47531f323eb37a826acd256a463e0e0b on master.