Stop accessing data from window.context in core parts of our logic

Created by: ijsnow

We store data on window.context. This makes writing unit tests hard because they will fail when trying to access data from there. It is also generally bad practice to extend globals in JS.

We should either:

1. Stop storing data there and fetch all data as we do in siteFlags
2. Change code architecture to only access global variables like this and pass it through the react application with react context (not props everywhere like isLightTheme). We can then use this info to create things like eventLogger on the fly rather than importing it as a global variable.
3. Both?