gke-node-pool default name conflict fixed

[sharabiani]

This PR fixes the default name conflicts when multiple gke-node-pool is added to a blueprint with a same machine type and without specifying a name.

The machine_type used to be considered as name for the node-pool so in the above scenario multiple modules were trying to create the same node-pool. Now the default name will be machine_type + module id which is unique blueprint-wide.

Sample node-pool name: c2-standard-60-computepool-03

Manual tests:

1- A blueprint including multiple gke-node-pool with the same name created:

  - id: compute_pool
    source: modules/compute/gke-node-pool
    use: [gke_cluster]

  - id: compute_pool_01
    source: modules/compute/gke-node-pool
    use: [gke_cluster]

  - id: compute_pool_02
    source: modules/compute/gke-node-pool
    use: [gke_cluster]

2- Blueprint deployed succesfully and verified by GCP Console nodepools creation with names like the sample name above

3- A new node-pool added to the blueprint:

  - id: compute_pool
    source: modules/compute/gke-node-pool
    use: [gke_cluster]

  - id: compute_pool_01
    source: modules/compute/gke-node-pool
    use: [gke_cluster]

  - id: compute_pool_02
    source: modules/compute/gke-node-pool
    use: [gke_cluster]

  - id: compute_pool_03
    source: modules/compute/gke-node-pool
    use: [gke_cluster]

4- Blueprint deployed succesfully and verified by GCP Console only the new nodepool created with name like the sample name above

5- Destroyed the the cluster successfully