Sqlalchemy configure_mappers is not instrumented

[Dizzzmas]

Recently I had to spend quite a bit of time tracking down SQLAlchemy configure_mappers call which was causing considerable amounts of latency in my application.

Would be nice to have it instrumented via X-Ray.

[willarmiros]

Hi @Dizzzmas thank you for the suggestion to improve our SQLAlchemy support, we will add it to our backlog!