switch to use protobuf for internal data structure in DB

app/dbentry.proto

@@ -0,0 +1,17 @@
+syntax = "proto3";
+package app;
+
+import "google/protobuf/timestamp.proto";
+
+option go_package = "github.com/tlinden/anydb/app";
+
+message DbEntry {
+  string Id = 1;
+  string Key = 2;
+  string Value = 3;
+  bytes Bin = 4;
+  repeated string Tags = 5;
+  google.protobuf.Timestamp Created = 6;
+  uint64 Size = 7;
+  bool Encrypted = 8;
+}