Separate tree building and filtering phases

[PaulTaykalo]

Currently dep viz tries to perform all the things by getting dependencies, filtering items
But it's possible that we can use intermediate dependencies file (as .JSON) and perform post filering by another phase. this will help to perform fast filtering of some system libraries and some unneded classes without the need to regenerate the tree again

This also can be done to regenerate inheritance only graph

• generate intermediate output (unfiltered json)
• allow to use (unfiltered json) as a source and only apply filtering to it
• allow to use multiple jsons and merge them