Break away from the Tink repositories Manager

[chrisdoherty4]

Hegel currently uses the Tink repositories manager and utility functions for building a client it can use to retrieve custom resources. The manager builds in a bunch of indexes for the various Tink repository types some of which are unnecessary in this context. Those indexes force us to depend, implicitly, on additional custom resources such as Workflow and Template even though Hegel only cares about the Hardware resource.

We should break away from the manager components of the Tink repository and just implement what we need in Hegel. This gives an opportunity to move away from the manager also as that's generally intended for controllers. Instead, we could leverage the controller runtimes Cluster type that has a small surface area and scope.