Redesign of the admin interface.

Main changes:
 - Splitted up settings and users into two separate pages.
 - Added verified shield when the e-mail address has been verified.
 - Added the amount of personal items in the database to the users overview.
 - Added Organizations and Diagnostics pages.
   - Shows if DNS resolving works.
   - Shows if there is a posible time drift.
   - Shows current versions of server and web-vault.
 - Optimized logo-gray.png using optipng

Items which can be added later:
 - Amount of cipher items accessible for a user, not only his personal items.
 - Amount of users per Org
 - Version update check in the diagnostics overview.
 - Copy/Pasteable runtime config which has sensitive data changed or removed for support questions either on the forum or github issues.
 - Option to delete Orgs and all its passwords (when there are no members anymore).
 - Etc....

src/db/models/cipher.rs

@@ -355,6 +355,14 @@ impl Cipher {
         .load::<Self>(&**conn).expect("Error loading ciphers")
     }
 
+    pub fn count_owned_by_user(user_uuid: &str, conn: &DbConn) -> Option<i64> {
+        ciphers::table
+        .filter(ciphers::user_uuid.eq(user_uuid))
+        .count()
+        .first::<i64>(&**conn)
+        .ok()
+    }
+
     pub fn find_by_org(org_uuid: &str, conn: &DbConn) -> Vec<Self> {
         ciphers::table
             .filter(ciphers::organization_uuid.eq(org_uuid))