Adds the foundation for the repository implementation with abstract Repository, Unit Of Work and Cache provider.

Adding the Query object implementation.
Adds the ModelDtoMapper, which is still a WIP.
Adds the initial implementation of the IContentRepository with dependencies.

src/Umbraco.Core/Persistence/Caching/IRepositoryCacheProvider.cs

@@ -0,0 +1,49 @@
+using System;
+using System.Collections.Generic;
+using Umbraco.Core.Models.EntityBase;
+
+namespace Umbraco.Core.Persistence.Caching
+{
+    /// <summary>
+    /// Defines the implementation of a Cache Provider intented to back a repository
+    /// </summary>
+    internal interface IRepositoryCacheProvider
+    {
+        /// <summary>
+        /// Gets an Entity from the cache by Type and Id
+        /// </summary>
+        /// <param name="type"></param>
+        /// <param name="id"></param>
+        /// <returns></returns>
+        IEntity GetById(Type type, Guid id);
+
+        /// <summary>
+        /// Gets an Entity from the cache by Type and Ids
+        /// </summary>
+        /// <param name="type"></param>
+        /// <param name="ids"></param>
+        /// <returns></returns>
+        IEnumerable<IEntity> GetByIds(Type type, List<Guid> ids);
+
+        /// <summary>
+        /// Gets all Entities of specified type
+        /// </summary>
+        /// <param name="type"></param>
+        /// <returns></returns>
+        IEnumerable<IEntity> GetAllByType(Type type);
+
+        /// <summary>
+        /// Saves the Entity
+        /// </summary>
+        /// <param name="type"></param>
+        /// <param name="entity"></param>
+        void Save(Type type, IEntity entity);
+
+        /// <summary>
+        /// Deletes the Entity from the cache
+        /// </summary>
+        /// <param name="type"></param>
+        /// <param name="entity"></param>
+        void Delete(Type type, IEntity entity);
+    }
+}