Set up a Neuroglancer tool

In ndip/public-packages/nova-trame#85 (closed) and ndip/public-packages/nova-trame#86 (closed) we've established that it's possible to run Neuroglancer in Trame and connect our data to it. If we want to move forward, then I can setup a simple Trame-based tool that uses it. The user will be able to connect to any remote Neuroglancer data server from it, and we can also provide one control for adding local TIFF stacks since that is our initial use case.