Use a nicer dict/object analogue for config
update github repo search algo

1. Now we start with a built-in configuration
2. It includes both the CI-Connect and OSGConnect orgs
3. You can specify the prefix for those tutorials in the github config
   param, if you like.
add --collection option and TUTORIAL_COLLECTION env var
allow installing multiple tutorials at once
enable setup scripts
implement collection aliases via config file