adjust checkstyle configurations to decrease violations

Adjust Storm's checkstyle configuration:

• 4-space indent instead of 2-space indent that is default with google_checks.xml
  • More hand-written code in Storm is 4-space indented than 2-space indented.
• exclude the thrift generated code from checkstyle
  • since we shouldn't be touching it anyways
• go with 120 character line-length limits instead of the default of 100 from google_checks.xml
  • This cuts ~70% of the line-length violations. We might wanna increase it even more. 140 would cut out ~90% of the line-length violations.

With those adjustments, the total number of violations will shrink by ~100,000 (~140,000 -> ~40,000).

We can decrease the existing violations even more if we upgrade the checkstyle version from 6.11.2 to 7.7. I figured this out after noticing that IntelliJ had different (& fewer) violations when I ran the checkstyle plugin on the same module in IntelliJ as compared to with cmdline maven. A further benefit of the newer checkstyle version is that it runs way faster. As in ~6+ times faster.