3 Display auto saving icons and message if logged in

[maddyjoe]

Part 3 of auto save EPIC
For logged in users let them know we are auto-saving their work

• icon for auto saved --->should be as per these designs. Although auto-save will happen whether logged in (into database) or logged out (local storage), we'll only display the icon if logged in.
• in the designs it now also displays the time of last autosave

Not in scope:

• auto-save variant message and warning message for no Internet connectivity (backlogged for now to slot into a future sprint)
• the design for toggling auto-save off, as we will look to backlog this and cover at a later date

[create-issue-branch]

Branch issues/268-3_Display_auto_saving_icons_and_message_if_logged_in created!