This adds functions for the helm-controller and source-controller from
Flux v2 [0]. The helm-controller depends on the source-controller and
so this includes a composite to wrap both. These components replace the
Helm Operator, which is now removed from the gating setup. The Helm Operator
function itself will be removed after a suitable migration period.
This also adds a format for Helm chart and Helm repository sourcing
to the versions catalog.
[0]: https://fluxcd.github.io/flux2
Closes: #372
Change-Id: I7287f1bb5b1ebd1dba9920cc0bed8c867720b4c1
Signed-off-by: Sean Eagan <seaneagan1@gmail.com>