Plugin packs

[MarioVilas]

Since the plugin manager can load plugins from any folder you tell it to, this could allow us to develop plugin packs - where the engine remains the same, but the plugins are focused on a specific area. For example, a pack for web analysis, a pack for malware analysis, etc.

The trickier part would be the data model, as currently we'd need to keep the same model for everything. This may or may not be a problem, we'll see.

[MarioVilas]

/cc @rrequero