Refactor maven pom detection system

[Riduidel]

MavenDetailsInfererEnhancer is way too complex.
We should split it by extracting all inner classes, and separate the pom lookup code from the dependency detection system.

Notice that the pom lookup code should be made more generic in order for order build tools to use it.

[Riduidel]

In fact, beside splitting that horrendous class into multiple small oens, it could be good to separate the maven pom detection from the maven pom processing in two different enhancers, then rewrite maven pom detection to also handle other package managers. This would impact the work on #234