Upgrading member repositories and services with tests
Gets the members services ensuring members xml is being handled correctly, fixes issue with the static variable holding the default member type properties (this was then persisted in mem and then reused across all member types). Added more unit tests to verify all.
Merge remote-tracking branch 'origin/6.2.0' into 7.0.2

Conflicts:
	src/Umbraco.Core/Constants-Conventions.cs
	src/Umbraco.Core/Models/ContentExtensions.cs
	src/Umbraco.Core/Persistence/Factories/MemberTypeReadOnlyFactory.cs
	src/Umbraco.Core/Persistence/Relators/PropertyDataRelator.cs
	src/Umbraco.Core/Persistence/Repositories/MemberTypeRepository.cs
	src/Umbraco.Core/Services/IMemberService.cs
	src/Umbraco.Core/Services/IMemberTypeService.cs
	src/Umbraco.Core/Services/MemberService.cs
	src/Umbraco.Core/Services/MemberTypeService.cs
	src/Umbraco.Core/Services/ServiceContext.cs
	src/Umbraco.Tests/Persistence/Repositories/MemberRepositoryTest.cs
	src/Umbraco.Tests/Persistence/Repositories/MemberTypeRepositoryTest.cs
	src/Umbraco.Tests/TestHelpers/Entities/MockedContentTypes.cs
	src/Umbraco.Tests/TestHelpers/Entities/MockedMember.cs
	src/Umbraco.Tests/Umbraco.Tests.csproj