Move kuma-gui to use workspaces

[johncowen]

Description

Since we started refactoring our application, the majority of our application "modules" in /src/app have been imagined as separate npm packages, just it has always been too much churn to move them/"promote" them to fully-fledged npm packages.

We also have certain usecases where we would like to publish or otherwise consume certain packages on their own, and/or move certain files into consumable packages (such as all our tooling configuration).

In order to start making our final steps towards these outcome we should move our repository to use workspaces:

• move the entire application into /apps/kuma-gui and have it be buildable/testable/deployable as usual.
• make a new workspace/package in /packages/config to house consumable configuration and have /apps/kuma-gui depend on this for all tooling configuration.
• on a case-by-case basis move each /src/app/* module into its own workspace/package, and have /apps/kuma-gui depend on it. These should not live in /apps but instead in /packages or possibly /modules (this decision is tbd)

The first point above can probably be a single PR, but the remaining two are probably several.