Added initial Maven project OSS info extraction.

This is work in progress as follows:

* UI in line with other agents (pending UX here and there eventually)
* project type detection heuristic is in place (checks for existing Maven 2/3 tasks)
* OSS extraction for the plugin project itself works, however, this is a Maven 2 project without modules only
 * multi module tests are consequently ignored still, insofar these require a respective test project setup

The main remaining task is to ensure multi module and especially Maven 3 compatibility; the latter might be an issue eventually, insofar Bamboo still facilitates the discontinued Maven 2.0.4 `MavenEmbedder` for its own surfaced dependency management, which I've also used now as requested. This feature is advertized and seems to work for Maven 3 as well though, see [Automatic dependency management with Maven 3](https://confluence.atlassian.com/display/BAMBOO/Setting+up+plan+build+dependencies#Settingupplanbuilddependencies-AutomaticdependencymanagementwithMaven3) (however, apparently Bamboo meanwhile shells out to the command line for the Maven tasks themselves, i.e. Maven dependency management and Maven project execution are handled via different Maven integrations).

I'll keep it at that until we've discussed the state of affairs and how to proceed via other channels; the pull request should probably not be merged yet accordingly.