* 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
* use typescript/no-redeclare for compatibility with ts overloads
* remove generics from getVariable() and overload it to only return undefined based on arguments
* update usages of getVariable()
* Remove generic from getInstanceState
* update usages of getInstanceState
* fix lint
* Refactor: Replaces initLock with state machine
* Refactor: removes some states for now
* Refactor: adds loading state in OptionsPicker
* Refactor: major refactor of load state
* Refactor: fixes updating graph in parallell
* Refactor: moves error handling to updateOptions
* Refactor: fixes the last cases
* Tests: disables variable e2e again
* Chore: removes nova config
* Refactor: small changes when going through the code again
* Refactor: fixes typings
* Refactor: changes after PR comments
* Refactor: split up onTimeRangeUpdated and fixed some error handling
* Tests: removes unused func
* Tests: fixes typing
* Refactor: moves all the newVariables part to features/variables directory
* Feature: adds datasource type
* Tests: adds reducer tests
* Tests: covers data source actions with tests
* Chore: reduces strict null errors