Problems with variables #1
Description
It seems the plugin has multiple problems with Grafana variables.
1.The "Query options" section disappears when adding a variable via the dashboard settings. As soon as the mongodb-grafana-datasource is selected in as data source for a variable of type query, the options for configuring the variable disappear without any error messages.
2. Using the Grafana dashboard variables in the Aggregation Pipeline when configuring a panel does not work. The grafana documentations state "Before queries are sent to your data source the query is interpolated, meaning the variable is replaced with its current value.", but this not seems to happen. I checked the log of the backend and I can see that the requested aggregation contains the unreplaced Grafana variables.