Example of deploying the operator with Flux source controller

[squaremo]

This example shows how to set up the operator and Flux's source controller so they can work together. It includes a subordinate example which shows how to create a GitRepository (a Flux source) and a Stack object that points to it.

This should remain a draft until the Flux support is released.

[squaremo]

We'll need to bump the default values for operator-version and crd-version once there's a release including Flux source watch (i.e., after #348). It will kind of work at present, but you need an image built from #348.