[java][jersey2] Add hook to customize SSL context, trust manager and host verifier

[sebastien-rosset]

This PR adds a new method that can be overridden to customize the SSL context, trust store, host verifier and keystore.

For example, this may be needed to disable certificate validation when the server is deployed in a development environment with a self-signed certificate, or when the key store needs to be customized.

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[sebastien-rosset]

@bbdouglas (2017/07) @sreeshas (2017/08) @jfiala (2017/08) @lukoyanov (2017/09) @cbornet (2017/09) @jeff9finger (2018/01) @karismann (2019/03) @Zomzog (2019/04) @lwlee2608 (2019/10) @bkabrda (2020/01)

[wing328]

LGTM