Add a way to browse/get "root" objects

[aronsemle]

As a client, I want to a way to progressively browse the address space. I want to start at the root(s), and allow a user to expand a tree and explore. This is a common experience in industrial products.

Currently the GET /objects route takes an optional typeId and includeMetadata flag. As a result I can ask for all objects of a certain objecttype OR get all objects. If I want to provide a progressive browse, I need to hack it on the client side (get everything, piece together relationships, etc). This is inefficient & won't scale for servers with many objects.

There a number of ways to do this. Note there could be one or more roots

• On the existing GET /objects route
  • Define a typeId that is "root" and considered special in the I3X address space
  • Add a filter option with the ability to look for hasParent=false
    • It’s probably good to start thinking about more advanced filters / wildcards as part of this and leave space in the spec for it
• Add a new API
  • Not ideal; seems like overkill unless it was more of a browse API
  • It seems like we already have this with /objects and /objects/{id}/related

[jwise-mfg]

Prototype used "/" -- we need to codify this in the spec.