Implement host probing retry with major refactoring

- Implement probe retry
- Switch to typical core/provider design pattern for HostProbingService
  and as a result decoupling the dependency between SR and HostLocationProvider

Change-Id: I33a15af580677ea376b421ac3e26f9821dcca844
4 files changed
tree: a8fdec71ac831a465a1f7e62d205f38771738ada
  1. BUCK
  2. app/
  3. pom.xml
  4. web/