Support copying attachments during clone/create/edit/transition

Update: Support for copying attachments for clone action has now been released.

Should include:

• issue actions
• when copying comments which contain an image
• When cloning issues using the Clone Issue action it would be good to have an option to copy attachments to the new issue. There are a number of use cases where this is useful, but a common one is simply to ensure that images embedded in issue descriptions are copied correctly.

Should be able to select which attachments to copy:

• an option to ignore duplicates
• For example, by type or only those referenced in the description
• Add option to "Copy latest attachment from trigger issue."

Need to ensure we consider:

• restrict file size
  • Both overall and individual
• Timeouts