Extract metrics.jar from collections-advisor-agent uber jar in runtime

[manoelcampos]

That will avoid having to place the metrics jar into some dir where the app is being executed.
That metrics.jar is load in the bootstrap class load because it's shared between the agent and the app.
This way, it enables the agent to store static data and the app to read it.

By requiring the sample jar to be into the app/agent dir so that the agent can load it on the bootstrap classloader, makes it more difficult to use the agent.
Since the agent is a uber jar that have the metrics as a dependency in the pom.xml, we can extract the metrics.jar dynamically from the uber jar and load it on the bootstrap class path.

For more details check #5.