[Java][WebClient] add ResponseEntity return for webclient

Created by: UnleashSpirit

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For now we done it by overriding templates but as I have a bit of time and I found that there is already an issue about that, I propose this PR fix: #5599 (closed)

For review (java) : @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) @nmuesch (2021/01)