Utility DB name => DB ID as a side help to init methods

[hemidactylus]

Not part of the main flow, but a utility method to resolve (Astra) db id from db name might be helpful.
This would enable init through DB name, although a stronger token is required - which is why this should stay as a side thing IMO.

Reference: https://github.com/LangStream/langstream/blob/0002679568db7fdaaf86cf5c563afb98a47a0ca9/langstream-agents/langstream-ai-agents/src/main/java/com/datastax/oss/streaming/ai/datasource/CassandraDataSource.java#L276-L281