Hide remove image, if there's no custom avatar

Fix #7308
Use addClass('hidden') and removeClass('hidden')
Merge branch 'master' into hide_remove_image_avatar
Merge branch 'master' into hide_remove_image_avatar
Remove OC.Router usage
Use $.hide() instead of .hidden for now

.inlineblock ranks higher than .hidden
Merge pull request #7340 from owncloud/hide_remove_image_avatar

Hide remove image, if there's no custom avatar