Create Room ORM example

`dataframe-jdbc` methods don’t work on Android because Android doesn’t properly support JDBC (`java.sql.*` is incomplete), so calling `DataFrame.readSqlQuery` may crash at runtime (see #1014).

We should add Android Databases IO support (#1725).

What we can do **now** to improve the situation is documentation for now — add an Android ORM integration example (similar to the existing Hibernate example). Room is the most common ORM on Android.

Start by locating the existing Hibernate integration example and the surrounding Android or database documentation. Add a comparable Room ORM integration example for Android, and verify that the documentation clearly demonstrates the intended DataFrame usage without relying on JDBC.

Written by the indexing model from the issue text.