[MD] Expose properties to allow customization for picker provided by data source plugin

[BionIT]

Is your feature request related to a problem? Please describe.

In #5717, we implemented a data source picker in order to unify the experience when selecting data source in devtools, tutorial, etc. While being used by plugins, this picker needs to be customized in order to satisfy the needs.

Describe the solution you'd like

We can expose the following properties for consumers

• placeholderText
• prepend
• defaultOption

In addition, we can expose a filter function property to allow consumers to define their filtering logic to hide incompatible/irrelevant data sources

Describe alternatives you've considered
Each consumer would need to write its own picker in order to customize things

Additional context

Add any other context or screenshots about the feature request here.

[seraphjiang]

looking forward to see some examples. It could be first party plugin like discover app