Java jersey OAuth2 add support for public client

[sbilz]

Java jersey OAuth2 add support for public client by a new method ApiClient.setOauthCredentialsForPublicClient(String clientId), which does not require the clientSecret as described in issue #13827

PR checklist

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  ./mvnw clean package 
  ./bin/generate-samples.sh
  ./bin/utils/export_docs_generators.sh
  

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cc @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)

[wing328]

LGTM. Thanks for the enhancement.