Merge branch 'stable-2.15'

* stable-2.15:
  Align Eclipse compiler settings with core Gerrit's
  Add standalone bazel build
  Remove .buckconfig
  Update commons-codec dependency
  Only consider commit objects when creating service user notes
  Remove unnecessary warning suppression
  Remove declaration of unthrown exception
  Remove buck build
  Format all Java files with google-java-format
  Remove unnecessarily nested else-clauses

Change-Id: I416b1bba7ca3faa14300b5031181234be69c3fea