Relocate webapp

Applies the following layout:

|--treeherder-service
   |-bin
   |-puppet
   |-requirements
   |-treeherder
   |---model
   |---webapp
   |-----static
   |-----urls.py
   |---otherapp
   |-manage.py
   |-tests
   |-vendor

you need to create a local settings file from treeherder/settings/local.sample.py to use the webapp