Problem Description: 

Users might need to sign a specific collection using the UI
The UI will show a button on collection version, collection or namespace views
and this button opens a modal for the user to confirm and perform the signing.

QA Criteria: 

• As a user I can click a button in the namespace view that starts signing task for all collections and versions under that namespace, once button is clicked a confirmation modal shows the summary of the sign operation (signing-service name, number of collections to be signed etc...)
• As a user I can click a button in the collection view to sign the entire collection (all of its versions) once clicked it shows a modal confirming I want to sign all the versions
• As a user I can click a button in the collection view to sign a specific version
• Only users with the sign permission are able to see and click that button
• The button must be in disabled state if GALAXY_COLLECTION_SIGNING_SERVICE settings is null.