Support `hints`

[marandaneto]

Description

This is needed for #1460 and #2650
Also for https://develop.sentry.dev/sdk/features/#http-client-errors -> PR
Hints are part of the Unified API.
Hints are generally a Map<String, Any>, on Java leverage the data bag with a typed class with helper methods.

[philipphofmann]

If we add an overload for beforeSend with a hint we can do this without a breaking change.