Add example/integration to demonstrate backend selection

### What

Setup example/integration that creates a bazel_dep to score_crypto module.
For the setup baselibs example/integration can be used as reference.
- [example/integration/MODULE.bazel](https://github.com/eclipse-score/baselibs/blob/main/examples/integration/MODULE.bazel#L14-L18)
- example/integration/.bazelrc
- extend workflow matrix ([example PR](https://github.com/eclipse-score/baselibs/pull/411))

The example integration should demonstrate the usage of the crypto component.
- configure of crypto daemon backend
- exemplary usage of crypto library API (ideally working test)

### Acceptance Criteria (DoD)

- example/integration which self includes score_crypto is present.
- example/integration/.bazelrc demonstrates backend selection via flags.
- example/integration demonstrates crypto api usage.

### How

_No response_

Start by comparing example/integration/MODULE.bazel and example/integration/.bazelrc with the baselibs references, then inspect the workflow matrix and the score_crypto integration entry points. Add the self-including example, backend-selection flags, and crypto API usage, ideally covered by a working integration test; verify all acceptance criteria and the workflow matrix.

Written by the indexing model from the issue text.