Move user/cover image files used in admin team area into the client folder

no issue
- fixes potential "mixed content" warnings if non-admin urls are redirected

ghost/admin/app/components/gh-posts-list-item.js

@@ -22,7 +22,7 @@ export default Component.extend(ActiveLinkWrapper, {
     }),
 
     authorAvatar: computed('post.author.image', function () {
-        return this.get('post.author.image') || this.get('ghostPaths.url').asset('/shared/img/user-image.png');
+        return this.get('post.author.image') || `${this.get('ghostPaths.subdir')}/ghost/img/user-image.png`;
     }),
 
     authorAvatarBackground: computed('authorAvatar', function () {

ghost/admin/app/components/gh-profile-image.js

@@ -36,7 +36,7 @@ export default Component.extend({
     },
 
     defaultImage: computed('ghostPaths', function () {
-        let url = this.get('ghostPaths.url').asset('/shared/img/user-image.png');
+        let url = `${this.get('ghostPaths.subdir')}/ghost/img/user-image.png`;
         return Ember.String.htmlSafe(`background-image: url(${url})`);
     }),
 

ghost/admin/app/components/gh-user-active.js

@@ -10,7 +10,7 @@ export default Component.extend({
     ghostPaths: inject.service('ghost-paths'),
 
     userDefault: computed('ghostPaths', function () {
-        return this.get('ghostPaths.url').asset('/shared/img/user-image.png');
+        return `${this.get('ghostPaths.subdir')}/ghost/img/user-image.png`;
     }),
 
     userImageBackground: computed('user.image', 'userDefault', function () {

ghost/admin/app/controllers/team/user.js

@@ -50,7 +50,7 @@ export default Controller.extend(ValidationEngine, {
 
     // duplicated in gh-user-active -- find a better home and consolidate?
     userDefault: computed('ghostPaths', function () {
-        return this.get('ghostPaths.url').asset('/shared/img/user-image.png');
+        return `${this.get('ghostPaths.subdir')}/ghost/img/user-image.png`;
     }),
 
     userImageBackground: computed('user.image', 'userDefault', function () {
@@ -61,7 +61,7 @@ export default Controller.extend(ValidationEngine, {
     // end duplicated
 
     coverDefault: computed('ghostPaths', function () {
-        return this.get('ghostPaths.url').asset('/shared/img/user-cover.png');
+        return `${this.get('ghostPaths.subdir')}/ghost/img/user-cover.png`;
     }),
 
     coverImageBackground: computed('user.cover', 'coverDefault', function () {