Ability to move issue to another project

Tasks:

• Create scaffold of service that will move issue to another project.
• Close old issue, add system note about moving issue to a new project.
• Create a new issue, add system note about issue being moved from old project.
• Check if issue can be moved to another project before executing service
• Check permissions when moving an issue (:admin_issue ability)
• Display select box for a new project when editing an issue
• Show only projects that issue can be moved into in that select box
• Add project select handler, helper and some permission filters to it
• Preserve as much information as possible, including author
• Prepare mechanisms that unfolds local references in issue description
• Rewrite issue description with references unfolding and add some specs for it
• Rewrite all system notes and comments attached to issue that is being moved
• Update Label so that is was able to create cross reference labels (separate MR)
• Add notifications about moving issue to another project
• Display confirmation alert/message when issue move has been requested
• Make it possible to undo selecting project where issue will be moved to
• Add column to issue, that will indicate if it has been moved to another project
• Do not allow to move issue that has been already moved
• Write top-to-bottom feature spec in RSpec instead of Spinach

UI:

Closes #3024 (closed)