Improve error handling in the Reconcile function

[jgomezve]

Handle errors coming from the APIC Client

[jgomezve]

Add a validation step to the request in the Reconcile method.
It could be that the rules in the request comply with the Schema but they can be invalid.

For example:

apiVersion: apic.aci.cisco/v1alpha1
kind: SegmentationPolicy
metadata:
  name: segpol1
spec:
  namespaces:
    - ns1
    - ns2
  rules:
    - eth: arp
      ip: icmp
      port: 80