Automatically detect kind

[malcolmholmes]

Currently, using actions that read files, the user needs to tell Grizzly whether a resource
includes an envelope or not, and if it doesn't include an envelope, the user must specify
a kind.

This PR adds in basic kind detection. It will first detect an envelope. If no envelope
present, it will ask each handler to detect its own resource type, hopefully resulting in
a kind that identifies that handler.

[julienduchesne]

Where is the datasource detection coming from?

[malcolmholmes]

Where is the datasource detection coming from?

At present, only enveloped and dashboard detection are implemented. Datasource presumably would be simple too.

[julienduchesne]

Where is the datasource detection coming from?

At present, only enveloped and dashboard detection are implemented. Datasource presumably would be simple too.

There's tests for it though. What am I missing?

[malcolmholmes]

There's tests for it though. What am I missing?

Yes, it either tests (a) that enveloped detection works on a kind that doesn't have its own detection yet or (b) without an envelope it throws an error.

[julienduchesne]

Yes, it either tests (a) that enveloped detection works on a kind that doesn't have its own detection yet or (b) without an envelope it throws an error.

Oh 🤦 . Indeed