Rework doc generation to simplify and centralize

Just do all doc generation in the hack::util::gen-docs instead of spread
around. We also only track the generated docs in a single file for the
whole tree.

.generated_docs

@@ -0,0 +1,64 @@
+.generated_docs
+contrib/completions/bash/kubectl
+docs/man/man1/kubectl-annotate.1
+docs/man/man1/kubectl-api-versions.1
+docs/man/man1/kubectl-attach.1
+docs/man/man1/kubectl-cluster-info.1
+docs/man/man1/kubectl-config-set-cluster.1
+docs/man/man1/kubectl-config-set-context.1
+docs/man/man1/kubectl-config-set-credentials.1
+docs/man/man1/kubectl-config-set.1
+docs/man/man1/kubectl-config-unset.1
+docs/man/man1/kubectl-config-use-context.1
+docs/man/man1/kubectl-config-view.1
+docs/man/man1/kubectl-config.1
+docs/man/man1/kubectl-create.1
+docs/man/man1/kubectl-delete.1
+docs/man/man1/kubectl-describe.1
+docs/man/man1/kubectl-exec.1
+docs/man/man1/kubectl-expose.1
+docs/man/man1/kubectl-get.1
+docs/man/man1/kubectl-label.1
+docs/man/man1/kubectl-logs.1
+docs/man/man1/kubectl-namespace.1
+docs/man/man1/kubectl-patch.1
+docs/man/man1/kubectl-port-forward.1
+docs/man/man1/kubectl-proxy.1
+docs/man/man1/kubectl-replace.1
+docs/man/man1/kubectl-rolling-update.1
+docs/man/man1/kubectl-run.1
+docs/man/man1/kubectl-scale.1
+docs/man/man1/kubectl-stop.1
+docs/man/man1/kubectl-version.1
+docs/man/man1/kubectl.1
+docs/user-guide/kubectl/kubectl.md
+docs/user-guide/kubectl/kubectl_annotate.md
+docs/user-guide/kubectl/kubectl_api-versions.md
+docs/user-guide/kubectl/kubectl_attach.md
+docs/user-guide/kubectl/kubectl_cluster-info.md
+docs/user-guide/kubectl/kubectl_config.md
+docs/user-guide/kubectl/kubectl_config_set-cluster.md
+docs/user-guide/kubectl/kubectl_config_set-context.md
+docs/user-guide/kubectl/kubectl_config_set-credentials.md
+docs/user-guide/kubectl/kubectl_config_set.md
+docs/user-guide/kubectl/kubectl_config_unset.md
+docs/user-guide/kubectl/kubectl_config_use-context.md
+docs/user-guide/kubectl/kubectl_config_view.md
+docs/user-guide/kubectl/kubectl_create.md
+docs/user-guide/kubectl/kubectl_delete.md
+docs/user-guide/kubectl/kubectl_describe.md
+docs/user-guide/kubectl/kubectl_exec.md
+docs/user-guide/kubectl/kubectl_expose.md
+docs/user-guide/kubectl/kubectl_get.md
+docs/user-guide/kubectl/kubectl_label.md
+docs/user-guide/kubectl/kubectl_logs.md
+docs/user-guide/kubectl/kubectl_namespace.md
+docs/user-guide/kubectl/kubectl_patch.md
+docs/user-guide/kubectl/kubectl_port-forward.md
+docs/user-guide/kubectl/kubectl_proxy.md
+docs/user-guide/kubectl/kubectl_replace.md
+docs/user-guide/kubectl/kubectl_rolling-update.md
+docs/user-guide/kubectl/kubectl_run.md
+docs/user-guide/kubectl/kubectl_scale.md
+docs/user-guide/kubectl/kubectl_stop.md
+docs/user-guide/kubectl/kubectl_version.md