Changed domains, configured links between VisaApplication and Applicant,created generic repository and repositories for domains

SchengenVisaApi/Domains/LocationDomain/Country.cs

@@ -0,0 +1,18 @@
+namespace Domains.LocationDomain
+{
+    /// Model of a country
+    public class Country : IEntity
+    {
+        /// Unique identifier of the <see cref="Country"/>
+        public Guid Id { get; private set; } = Guid.NewGuid();
+
+        /// Name of the country
+        public string Name { get; set; } = null!;
+
+        /// Located in Schengen area
+        public bool IsSchengen { get; set; }
+
+        /// List of <see cref="City"/> that country have
+        public List<City> Cities { get; set; } = null!;
+    }
+}