Tree name conflicts can occur if QM label is used for other purposes

[dmatch01]

Reference issue #295

AW jobs associated quota entitlements using the Kubernetes generic label key/value. The key is the associated quota tree name and the value is the quota tree node name with the associated quota entitlement. Here is an example:

Tree Name: app.kubernetes.io
Tree structure:

                           node name: my-quota-tree-root-node
                           cpu: 100
                                 |
                                 | 
_________________________________|_________________________________ 
|                                                                 |
|                                                                 |
node name: my-quota-tree-a-node                                   node name: my-quota-tree-123-node
cpu: 50                                                           cpu: 75
                                                                              |
                                                                              |
                                             _________________________________|______________________________ 
                                             |                                                                                                                            |
                                             |                                                                                                                            |
                                    node name: my-quota-tree-b-node                                         node name: my-quota-tree-c-node
                                    cpu: 25                                                                 cpu: 35

An AW definition to associate the quota entitlement to node: my-quota-tree-b-node would like:

apiVersion: mcad.ibm.com/v1beta1
kind: AppWrapper
metadata:
  name: my-appwrapper
  namespace: default
  labels:
    app.kubernetes.io: "my-quota-tree-b-node"
    . . .

Using a standard kubernetes label key app.kubernetes.io as a QM tree name could result in unexpected behavior from within the K8s ecosystem. Recommend to document best practices when creating a quota tree to avoid potential unexpected behavior.