SAM Lambda: user can configure event source, triggers

Having deployed a Lambda function that responds to events, the next logical step is for the user to configure the event source. This task is to design this interaction ready for implementation.

Some options that have been floated:
* a resource type sub-container view that either lists all possible event source types (S3 bucket etc) that can be added; user starts their event configuration from here with next steps to list resources of that type etc
* a view displaying 'favorite resources' (actual resource instances) that the user can control via add/remove command gestures (similar to regions); selecting a resource then invoking a command gesture gets the configuration process started
* a multi-step command gesture (similar to credentials) that lets the user select resource, then instance of type etc.
* what other approaches make sense?

The issue names no files, tests, or entry points. Begin by reviewing the existing regions and credentials interaction patterns mentioned in the issue, then compare the proposed event-source configuration flows. Done means producing a decided interaction design for selecting event-source types and resources, ready for implementation.

Written by the indexing model from the issue text.