XXX: currently only used for sharding by cookie. Will be extended
for use with all by=KEY cases.

To ensure that health checks from other Varnish instances succeed
in the self-sharding configuration, move the clause in vcl_recv
that is executed when remote.ip matches the ACL for cluster members
to the start of the subroutine.

XXX: currently returns a synthetic 400 response if the configured
cookie name is not found in the Cookie header (or if there is no
Cookie header). In a further iteration, we will add an optional
field defaultKey, which if present sets a string value to be used
as the sharding key if the key is not found.

XXX: testing this feature has revealed bugs in sharding by key
(using by=KEY) unless primaryOnly is also set to true. These will
be fixed in a further iteration.

Fixing the dataplaneapi has resolved this problem. In the process of
debugging, a logger was added to the dataplaneapi client code, which
will now be retained.

The ARG that sets the version string in the Dockerfile must evidently
be set *after* the FROM statement, so that git checkout is invoked
correctly.

git checkout with the Dockerfile ARG for the version tag apparently
wasn't working, so the latest version was checked out and built.
That version currently doesn't work in the haproxy container, so
the container did not come up.

XXX: validation of the dataplane response to the /sites request is
currently commented out. This is causing a problem with testing
and will be investigated further.

And update VMOD versions as necessary.

We will add an option to the BackendConfig CRD to use them if desired.

Purely cosmetic, but now it really sounds like a viking controller.

The haproxy version remains the same, but it's no longer necessary
to install from a backports repo.

The Pods were not always fully deleted when the next test began
in the longer e2e test script, which interfered with execution.

Now using the SUB feature of VMOD re2. This simplifies and
improves the scalability of the matching logic (one subroutine
call, rather than an if-elsif sequence that is as long as the
number of paths). Will also simplify the implementation of
pathType for k8s-1.22.

This is due at any rate, and in particular the more recent versions
of VMOD re2 and selector support the VCL_SUB feature.

This is necessary even if the controller is otherwise restricted to
a namespace. So we add a new ClusterRole to add the RBAC read rights
(wath, list and get) unconditionally for any controller instance.