Problem was that yaml unmarshal returned nested maps as
map[interface{}]interface{} which are then not marshal-able
to json because of that interface{} key type. This adds explicit
casting of the keys in the yaml value types to string which
then makes the values marshal-able to JSON in DB.
Fixes: #11537
* Fix: Handle empty nested keys on YAML provisioning datasources
As we provision a datasource via a YAML file, we attempt to transform the
file into sensible Go types that the provisioning code can use.
While this happens, there is a chance some of the keys nested within
the YAML array are empty.
This fix allows the YAML parser to handle empty keys by null checking
the return of `reflect.TypeOf` which according to the documentation:
> TypeOf returns the reflection Type that represents the dynamic type of i. If i is a nil interface value, TypeOf returns nil.
Can return nil.
* Add tests
* Add value types with custom unmarshalling logic
* Add env support for notifications config
* Use env vars in json data tests for values
* Add some more complexities to value tests
* Update comment with example usage
* Set env directly in the tests, removing patching
* Update documentation
* Add env var to the file reader tests
* Add raw value
* Post merge fixes
* Add comment
