add initial file scan and rescanning algorithms to hash all penumbra files

MareSynchronos/FileCacheDB/FileCache.cs

@@ -0,0 +1,14 @@
+using System;
+using System.Collections.Generic;
+
+#nullable disable
+
+namespace MareSynchronos.FileCacheDB
+{
+    public partial class FileCache
+    {
+        public string Hash { get; set; }
+        public string Filepath { get; set; }
+        public string LastModifiedDate { get; set; }
+    }
+}