Add path prefix parameter to setup_db script

This allows the script to be run from within scala unit tests.
This is needed, because the JVM doesn't allow changing directories
while running commands (in order to support multiple OS/file systems).
Store data as lat/lng, but read from DB as UTM
Refactor parts of GT service into companion object

For easier unit testing
Add trait for setting up fresh test databases
Integrate test database into scala tests
Fix typo
Merge pull request #100 from WorldBank-Transport/feature/scala-test-db

Create test database for scala tests