Java client, adds parameter classes

[spacether]

Java client, adds parameter classes

• parameter classes added
• tests added of parameters with schema serialization
• parameter documentation added to readme

Future

• add an operation parameters class
  • Contains HeaderParametersSerializer, QueryParametersSerializer, PathParametersSerializer, CookieParametersSerializer
  • ingests the parameters map
  • outputs the serialized info needed for header, query, path, cookie

PR checklist

• Read the contribution guidelines.
• Pull Request title clearly describes the work in the pull request and Pull Request description provides details about how to validate the work. Missing information here may result in delayed response from the community.
• Run the following to build the project and update samples:

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

  Commit all changed files.
  This is important, as CI jobs will verify all generator outputs of your HEAD commit as it would merge with master.
  These must match the expectations made by your contribution.
  You may regenerate an individual generator by passing the relevant config(s) as an argument to the script, for example ./bin/generate-samples.sh bin/configs/python*.
  For Windows users, please run the script in Git BASH.