feat: add workflow editor shortcuts (#3382)

[perzeuss]

Description

This PR brings shortcuts to the workflow editor as described in #3382. The following shortcuts are introduced:

Keyboard Shortcut	Function	Hint
Delete	Deletes the selected edge	Hint: This was previously the backspace key, but I found that delete is more intuitive. We should note this in the release.
Delete	Deletes the selected node
Ctrl + C	Copies the selected node
Ctrl + X	Cuts the selected node
Ctrl + V	Pastes a copied or cut node
Ctrl + Alt + D	Clones the selected node

Type of Change

• [x] New feature (non-breaking change which adds functionality)
• [ ] This change requires a documentation update, included: Dify Document

How Has This Been Tested?

I tested it manually in the development mode with the following steps:

• [ ] Create Workflow or Chatflow
• [ ] Add a Classifier node, define two classes and change the model
• [ ] Assign two End/Answer nodes to the Classifier node
• [ ] If you added Answer node, define a random word as answer so that we can publish the flow without issues
• [ ] Select the Classifier node and press Ctrl + C
• [ ] Press Ctrl + V
  • [ ] The Node should be copied to the workflow, the name should have the number 2 at the end
  • [ ] The copied node should be selected
  • [ ] The copied node should show the plus icon for the ingoing and outgoing edges
  • [ ] The copied node should have the same classes and the same llm configured
  • [ ] The copied node should not connected to another node (no edges have beend added)
  • [ ] Press Ctrl + V again
  • [ ] Another node should be copied at the same place as the previously copied node
  • [ ] It should have a 3 at the end
  • [ ] Select the 3rd Classifier node and press Delete
  • [ ] The 3rd Classifier node should be deleted
  • [ ] Select the 2nd Classifier node and press Delete
  • [ ] The 2nd Classifier node should be deleted
  • [ ] Save the workflow, it should work without issues
• [ ] Select the Classifier node and press Ctrl + X
  • [ ] The classifier node should have been deleted, as well as the edges
  • [ ] Add a new Classifier node and connect all edges again
  • [ ] Save the workflow, it should work without issues
• [ ] Reload the page while the workflow editor is open
• [ ] Select the Clasifier node and press Delete
• [ ] Reload the workflow
• [ ] The node should still be deleted
• [ ] Add a new Classifier node and connect the edges
• [ ] Select the Classifier node and press Ctrl + Shift + D
• [ ] The Classifier node should have been duplicated
• [ ] Reload the page the workflow editor is open
• [ ] The duplicated Classifier node should still be there
• [ ] Select the duplicated node and press Delete
• [ ] Publish the workflow, it should work without issues
• [ ] Select the Classifier node
• [ ] Press Ctrl + C and Ctrl + V
• [ ] The Classifier node should have been duplicated
• [ ] Reload the page the workflow editor is open
• [ ] The duplicated Classifier node shuld still be there
• [ ] Click on the Dropdown-Button (top right) to publish the flow
• [ ] Click on the white button to restore the flow
• [ ] A preview should be opened where the duplicated Classifier node is not visible
• [ ] Restore to this version
• [ ] The duplicated Classifier node should no longer exist

Suggested Checklist:

• [x] I have performed a self-review of my own code
• [ ] I have commented my code, particularly in hard-to-understand areas
• [x] My changes generate no new warnings
• [x] I ran dev/reformat(backend) and cd web && npx lint-staged(frontend) to appease the lint gods
• [ ] optional I have made corresponding changes to the documentation
• [ ] optional I have added tests that prove my fix is effective or that my feature works
• [ ] optional New and existing unit tests pass locally with my changes