* wip
* make diff easier to read
* Update template_srv getVariables to return new TypedVariableModel
* update VariableType to use the type from TypedVariableModel
* tidy things up
* Chore: Use type-accurate mock variables in tests
* Chore: Type VariableState to use TypedVariableModel
* fix typo
* remove type assertion from template_srv.getVariables
* undo whatever changes i did to swagger spec