First support for scoped modules, removing modules

ModuleIntrinsics use now scoped modules, as they can live in different
scopes.
SessionStateScope now contains a reference to the SessionState it lives
in. This allows access to the correct SessionState through the scope, at
ModuleIntrinsics require it for imorting and removing members.
Added hint to remove a workaround
Added a test, updated test TODOs
TODOs for upcoming Export-ModuleMember tests
Added tests for Export-ModuleMember