[SPIKE] Namespace /mobify

[vcua-mobify]

This is a POC of #1767

This PR shows how we can use the site alias defined in default.js as a namespace for the /mobify paths and for entries in local storage / cookie storage.

The document for this spike can be seen here: https://salesforce.quip.com/RaYKAunGpS3K

Testing this POC:

1. Check out the code base
2. Set an env variable called LOCAL_ENV_NAMESPACE to global
3. Start the app. See that /mobify paths are namespaced. ie. /global/mobify/...
4. Create a local.js config file and set the default site to RefArch
5. Set LOCAL_ENV_NAMESPACE to us
6. Restart the app. See that /mobify paths have a different namespace. ie. /us/mobify/...

[vcua-mobify]

#1824, which sets the stage for adding a namespace has been merged in