Added authentication and authorization, updated dependency injections, removed hard-coded connection string

SchengenVisaApi/Domains/Users/Role.cs

@@ -0,0 +1,13 @@
+namespace Domains.Users
+{
+    /// Role of <see cref="User"/>
+    public enum Role
+    {
+        /// Requests visa applications
+        Applicant,
+        /// Approves or declines applications
+        ApprovingAuthority,
+        /// Manages approving authorities
+        Admin
+    }
+}