* feat(loki-query-editor): create base editor component
* feat(loki-query-editor): update editor to use loki query type
* feat(loki-query-editor): add custom variable support to datasource
* feat(loki-query-editor): prevent errors when no label is present
* Add unit test for LokiMetricFindQuery
* Update datasource test
* Add component test
* Add variable query migration support
* feat(loki-query-editor): add migration support for older-format variables
* Fix enum capitalization for consistency
* Move attribute to the top of the class
* Remove unnecessary from()
* Update capitalization of new enum
* Fix enum capitalization in component
* feat(loki-query-editor): replace unnecessary class with class method
