Introduce new spring profiles "nflow.mysql" and "nflow.postgresql".

New configuration options nflow.db.h2.tcp.port and nflow.db.h2.console.port in engine to start the H2 remote connection and web UI.

Database configuration options new support optional dbType prefix. For example
"nflow.db.mysql.password" is checked before "nflow.db.password".

StartNflow now creates Spring Environment before starting Jetty so that server port and other information can be loaded from Environment. Additionally a Map of environment properties can be given to start method to override any options per test.

Removed NflowRunner and created a NflowServerRule instead. Use it with @ClassRule (or @Rule if you want to start/stop the server befor each test method).

Enabled parallel tests threads.