* Add better error messaging
- Ensure it's clear to users what action needs to be taken if an operation ID cannot be found
- Add test
* Display resource picker for trace exemplar queries
* Remove unneeded test
* Update tests
* Update types
* Mark datasource as supporting traces
* Add logic to transform exemplar query to traces query
* Render appropriate editor
* Run trace query for exemplars
* Refactor out common functions
- Add function to retrieve first/default subscription
* Add route for trace exemplars
* Update logic to appropriately query exemplars
* Update traces query builder
* Update instance test
* Remove unneeded import
* Set traces pseudo data source
* Replace deprecated function calls
* Add helper for setting default traces query
* Don't show resource field for exemplars query
* When resetting operation ID for exemplars set query to default
- Update tests
* Update query header to appropriately set the service value
* Fix response frame creation and update tests
* Correctly select resource
* Convert subscriptionsApiVersion to const
* Add feature toggle
* Remove unneeded error check
* Refactor to reduce cyclomatic complexity
* Add util function for parsing resultformat
* Make use of util
* Remove unneeded types
* Move types to their own file
* Move getApiUrl to utils
* Move traces functions to separate file
- Add separate helper for building trace string queries
* Add helper for determining resources
* Add test for RetrieveResources
* Don't append twice
* Refactor tests
