[Enhancement] Use SonarQube to run static code analysis for detecting bugs early

**Is your enhancement request related to a problem? Please describe.**
Current code analysis tool is not able to detect unused variables, which can be potential bugs. Using SonarQube can mitigate this problem.

**Describe the solution you'd like**
Integrate SonarQube to Pulsar's build process.

**Describe alternatives you've considered**

Not yet.

Start by reviewing Pulsar's build process and the current code-analysis tooling to identify where static analysis is configured. Integrate SonarQube into that process so unused variables and other detected bugs are reported during builds; done means the project runs SonarQube analysis as part of its build workflow.

Written by the indexing model from the issue text.