Exception thrown in ZipLocation model

### Problem
Cannot register successfully if mailing address info is not provided. This is an issue because mailing address is not a requirement during registration. Registration is only completely successful if all inputs are provided during registration.

There are currently [Required] attributes for Address, City, State, and ZipCode in our ZipLocation model. Those attributes shouldn't be there but removing them and creating a new migration doesn't help. EF still doesn't accept empty strings and values in our design (ID doesn't update/stays at 0)

### Exception Thrown
Validation error thrown in ZipLocation model.

### Quick fix
Create mock data to assign to ZipLocation properties upon registration. This data are constants and can be found in ECS.Constants/Data Access/ZipLocationConstants.cs.