Provisioning: Add Validation and Mutation for Connection resource (#115596)

* WIP: mutator added, start working on validator

* first validator iteration

* second validator iteration

* wip: working on integration tests

* re-working mutation and validation, using Connection interface

* fixing some rebase things

* fixing integration tests

* formatting

* fixing unit tests

* k8s codegen

* linting

* moving tests which are available only for enterprise

* addressing comments: using repo config for connections, updating tests

* addressing comments: adding some more info in the app and installation

* fixing app data

* addressing comments: updating connection implementation

* addressing comments

* formatting

* fixing tests

apps/provisioning/pkg/connection/connection.go

@@ -0,0 +1,16 @@
+package connection
+
+import (
+	"context"
+)
+
+//go:generate mockery --name Connection --structname MockConnection --inpackage --filename connection_mock.go --with-expecter
+type Connection interface {
+	// Validate ensures the resource _looks_ correct.
+	// It should be called before trying to upsert a resource into the Kubernetes API server.
+	// This is not an indication that the connection information works, just that they are reasonably configured.
+	Validate(ctx context.Context) error
+
+	// Mutate performs in place mutation of the underneath resource.
+	Mutate(context.Context) error
+}