ref: Create static & mutable Config providers so some values can be overridden in memory

[ryan953]

We want to be able to override stuff like placement, but some things like sentryOrigin cannot be overridden because that would cause the whole <ApiProxyContextProvider> to re-connect and be a weird experience.

So we have the <StaticConfigProvider> which wraps the whole app and nothing inside it can be changed.
Then down below we have <MutableConfigProvider> where the fields can be changed. If something below here depends on a field then it will be updated to use the new value. This means that fields like placement can be updated without any problems, other fields like debug and sentryOrigin can be updated, but nothing lower really uses them. This is a limitation that maybe we can address in a followup iteration.

It's important is not to re-render <ApiProxyContextProvider> or the other providers.