feat(context): add support for binding configuration and injection

[raymondfeng]

Reactivation of #983 based on requirements illustrated by #2249.

1. Add context.configure() to configure bindings
2. Add context.getConfig/getConfigSync() to look up configuration for a binding
3. Add @config, @config.getter, and @config.view to receive injection of configuration

Checklist

• npm test passes on your machine
• New tests added or existing tests modified to cover all changes
• Code conforms with the style guide
• API Documentation in code was updated
• Documentation in /docs/site was updated
• Affected artifact templates in packages/cli were updated
• Affected example projects in examples/* were updated