Implement upload via "Add image" on New file pages

Disabled edit button on pages with not existing files (new file pages), enabled the upload button
starts the upload workflow. Edit workflow so no new page will be created if upload starts via new file page.
Simply reload the page after finished upload.

Bug: 58311
Change-Id: I16d969f2a84c25376468bdb4c0458fe3426b92ee
Merge "Implement upload via "Add image" on New file pages"