* 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
* make createBaseVariableModel take the variable type
* 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: move constants to own file
* Chore: moves safe* functions to grafana/data
* Chore: moves safe* functions to grafana/data
* Chore: adds VariableQueryEditorProps and deprecates VariableQueryProps
* Chore: remove getDefaultVariableAdapters function
* Chore: moves transaction status to types
* Chore: fix tests that do not initialise TemplateSrv
* Chore: change space when stringifying
* Chore: revert safe* func move
* Chore: remove circular dependency in Explore utils
* Variables: adds drag and drop in variables list
* Refactor: fixes after PR comments
* Chore: updates after PR comments
* Refactor: adds styles during dragging
* Docs: update doc
* Chore: pushing Drone
* Performance: Standardize lodash imports to use destructured members
Changes lodash imports of the form `import x from 'lodash/x'` to
`import { x } from 'lodash'` to reduce bundle size.
* Remove unnecessary _ import from Graph component
* Enforce lodash import style
* Fix remaining lodash imports
* Refactor: Adds getNextAvailableId
* Refactor: Hides DependencyGraph button if there are no dependencies
* Refactor: Changes the new button
* Refactor: Removes usages of NEW_VARIABLE_ID
* Refactor: Reverts the new button
* 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