Simpler, more powerful request action types

Right now there are 16 action types for requests. I think that can reduced to 4 while also preparing us for multi-operation requests at the same time.

Right now, for instance:

```
READ_RESOURCES_PENDING
READ_RESOURCES_SUCCEEDED
```

this could instead just be:

```
REQUEST_PENDING
REQUEST_SUCCEEDED
```

with a `crudAction` attribute. In the future, `crudAction` could possibly be an array supporting multiple types (although there would need to be a way to specify what resources are affected by what action).

The issue names no files, tests, or entry points. Start by tracing the existing 16 request action types and their consumers, then work out the shared action shape and how crudAction would represent operations. Done requires an agreed design for reducing the action types and supporting future multi-operation requests.

Written by the indexing model from the issue text.