Improve "copy project" feature

The current feature shows two issues:

• projects are not sorted alphabetically on the list, making it hard to find a given project -> sort on id, and present label in parenthesis after id instead
• only projects where user is an explicit member are listed, this is annoying for admins => there should be a free input for admins, allowing to set a given project id: if input is not blank, the select value is ignored. If project does not exist, an alert is shown (or validation error)