Work items: Add edit button to title and description

Changes the layout and behavior of the "Edit" button to affect both the title and description, rather than only description. Title is no longer editable except in the "Edit" state activated from the edit button.

UX Details

• On "Edit", title and description appear in an editable state. Save and cancel buttons appear below.
  • Only pressing "Save changes" or "Cancel" returns to read state.
• Save button is always active, user can press save without changing anything (whether this actually makes a call is up to engineering).
• Work item type is not included in this edit form, this will be handled in a separate workflow as it will impact the entire page and can result in confirmation prompts.
• Template selection is shown in the editor, but for MVC may be broken out as that work is separate from this. A design is included showing the template selection outside of the editor.
• Ensure title is the pages <h1> component in the read state.