added uploading dataset and drag & drop support

[AjayThorve]

Demo is in working condition (can drag/drop datasets and generate graph viz) with a switch to start forceatlas2 rendering.

pendng is get/post pagify plugin for downloading queried datasets(currently sending via simple peer channels.

Edit: Implemented pagify plugin for downloading queried datasets

[AjayThorve]

@trxcllnt this is ready for review. Resolved most of the issues you mentioned.

Still pending is better user session tracking, which I'll push out in a follow-up PR