Rework backing storage system

Step one: Copy the struct definitions over into a new, dedicated
submodule
Step two: Make a generator script
Step three: Define helper functions for various queries

storage-new/models/UserAuthentication.go

@@ -0,0 +1,7 @@
+package models
+
+type UserAuthMethod struct {
+	UserId     string
+	AuthMethod AuthenticationMethodType `gorm:"type:auth_method_type"`
+	Token      []byte
+}