This replaces the semantic import for the Security framework with a
classic one. Semantic imports are currently not compatible with Kotlin
Multiplatform Mobile projects which makes OLMKit (and consequently
the iOS Matrix SDK) unusable in KMM.
Fixes: https://github.com/matrix-org/olm/issues/67
Signed-off-by: Johannes Marbach <n0-0ne@mailbox.org>
Improve ObjC wrappers so that they can use a pickle key provided by the olm lib user.
This new behavior is optional to not break existing usage.
It is retro compatible and use pickle versioning already in place.
Existing key will be unpickled with pickle v1 and pickled with pickle v2 if an external pickle key is provided.
