As a developer I want to provide a single file to configure my application and functions

[shaunsmith]

To support integration with CI/CD platforms and tools and to make it easier for a developer to capture, version, and deploy application configuration for a given context the Fn cli should support applying a set of configuration settings contained in a file rather than just setting individual config properties.

The proposed revised command structure supports configuration management using fn set:

fn set config app <app> <key> <value>
fn set config route <app> </path> <key> <value>

fn set should also accept a file (with an appropriate command line switch) with configuration, e.g.,

fn set config [app|route] <app> --f /path/to/my/config.yaml

Discussion questions:

1. Should a config.yaml be a peer to app.yaml and only apply at the application level, but with support for nested functions suitable labeled?
2. If a config.yaml could be applied to an individual route/function then could it simply be a list of key/value pairs with no other structure?