.xl node removal import with streaming sector import

[DoctorPresto]

Hide or don't import nodes which have been removed by .xl.

-ability to import .xl files separately from sectors and have them take effect?

-automatically import .xl files in the resources folder of the Wolvenkit project

Not sure if we should import the nodes, mark them as deleted and hide them or just not import them?

[Simarilius-uk]

That was totally not what I meant, but is also a good idea.