improve telemetry to include android api level version

[baywet]

It's currently really hard to determine which API level we should support as we don't have telemetry on that aspect for the SDK.
We should first detect we're running on android and then read the API level information.
This information should be added in the telemetry handler.
The telemetry handler currently logs the following information [SdkVersion=graph-java/v2.3.2, graph-java-core/v1.0.5 (featureUsage=0) java/1.8.0_252]

Note: today android calls seem to be logged as java/0 as System.GetProperty("java.version") seems to return 0 on android (to validate)

Note: the current user-agent is set by okhttp to okhttp/x.x.x today, this wasn't the case when using URL connection which was providing runtime information (environment, java runtime version, etc) like Dalvik/2.1.0 (Linux; U; Android 10; SM-A516U Build/QP1A.190711.020) or Java/1.7.0_80 or Apache-HttpClient/4.5.2 (Java/1.8.0_121). Should we change that as well?
AB#6845