Fix attachment creation

[lucasbordeau]

Scope & Context

• Attachment creation doesn't return signed token for fullPath property and thus the Apollo cache is broken, we need to refresh the app
• When going to files tab then coming back to rich text editor and inserting an image, all images lose their token
• Ideally we want to fix this in the backend at query result getters

Improvements :

• Modify the file name in attachment when it is modified from rich text editor
• Delete the attachment when it is removed from the rich text editor ?

[lucasbordeau]

@Weiko Shouldn't we add another property signedFullPath to disambiguate ? Seems like fullPath can be either signed and not signed ?