Fix AdoptedResources functionality for CapacityReservations (#268)

**Issue #, if available:** aws-controllers-k8s/community#2485

**Description of changes:**
This PR adds the following hooks for CapacityReservations.

1. `sdk_read_many_post_set_output` - This hook is required to correctly set/update instance count for reservations while/after they are adopted.
2. `sdk_update_post_build_request` - This hook is needed to add support to update/modify capacity reservations using the `additionalInfo` reserved field.

The new AdoptedResource config looks as follows,
```
apiVersion: services.k8s.aws/v1alpha1
kind: AdoptedResource
metadata:
  name: test-adopt-existing-capacity   # name of the adopted resource
spec: 
  aws:
    nameOrID: cr-XXXXXXXXX     # ID of the actual capacity reservation in AWS
  kubernetes:
    group: ec2.services.k8s.aws
    kind: CapacityReservation
    metadata:
      name: test-adopt-capacity # name of the K8s capacity reservation resource created by ack-ec2-controller
      namespace: default
```
Resources can also be adopted [using annotations](https://aws-controllers-k8s.github.io/community/docs/user-docs/features/#resourceadoption) (only if [ResourceAdoption feature gate is enabled in the cluster](https://github.com/aws-controllers-k8s/ec2-controller/blob/b6dff777c35d03335ebb0c3ffca5ee7577e70f18/helm/values.yaml#L172)) with following config,
```
apiVersion: ec2.services.k8s.aws/v1alpha1
kind: CapacityReservation
metadata:
  name: test-adopt
  annotations:
    services.k8s.aws/adoption-policy: "adopt"
    services.k8s.aws/adoption-fields: | 
      {"capacityReservationID": "cr-XXXXXXXXXX"}
```

By submitting this pull request, I confirm that my contribution is made under the terms of the Apache 2.0 license.

Author: fizashaikh