kubeadm: allow to provide patch inline in inventories

Specifying one directory for kubeadm patches is not ideal:
1. It does not allow working with multiples inventories easily
2. No ansible templating of the patch
3. Ansible path searching can sometimes be confusing

Instead, provide the patch directly in a variable, and add some quality
of life to handle components targeting and patch ordering more
explicitly (`target` and `type` which are translated to the kubeadm
scheme which is based on the file name)

roles/kubernetes/kubeadm_common/defaults/main.yml

@@ -0,0 +1,14 @@
+---
+kubeadm_patches_dir: "{{ kube_config_dir }}/patches"
+kubeadm_patches: []
+# kubeadm_patches:
+# - target: kube-apiserver|kube-controller-manager|kube-scheduler|etcd|kubeletconfiguration
+#   type: strategic(default)|json|merge
+#   patch:
+#    metadata:
+#      annotations:
+#        example.com/test: "true"
+#      labels:
+#        example.com/prod_level: "{{ prod_level }}"
+# - ...
+# Patches are applied in the order they are specified.