Inventory plugin: Support of ExaCC/CS database nodes

[jewdba]

Issue Report

Describe the issue

According to the documentation, only DBsystems are supported to become ansible managed nodes
https://github.com/oracle/oci-ansible-collection/blob/master/docs/inventory_plugin/index.rst

However, we already had a look at the code and we were able in our LAB to add the "db nodes" of our ExaCC VMclusters as ansible managed nodes.
/20160918/VmCluster/ListVmClusters

Nevertheless, the oci plugin is awaiting vnic details (plugins/inventory/oci.py) to extend host_vars, which do not exist on ExaCC/CS VMcluster as network resources are attached through a "VMclusterNetwork" resource.

Thus, by default the plugins/inventory/oci.py method build_inventory_for_db_host stops executing while retrieving the VNIC details

           vnic = oci_common_utils.call_with_backoff(
                virtual_nw_client.get_vnic, vnic_id=db_host.vnic_id
            ).data

            self.debug(
                "VNIC {0} is attached to db_host {1}.".format(vnic.id, db_host.id)
            )

Would you agree to add "try except" block? Thus, even if network details are still missing we could at least retrieve the list of nodes :)

Expected behavior

List database nodes as ansible managed nodes

Environment

• OS version: macOS 13.5.1 (22G90)

• Ansible version:

# oci-ansible-collection % ansible --version
ansible [core 2.15.3]
  config file = None
  configured module search path = ['/Users/jew/.ansible/plugins/modules', '/usr/share/ansible/plugins/modules']
  ansible python module location = /usr/local/Cellar/ansible/8.3.0/libexec/lib/python3.11/site-packages/ansible
  ansible collection location = /Users/jew/.ansible/collections:/usr/share/ansible/collections
  executable location = /usr/local/bin/ansible
  python version = 3.11.5 (main, Aug 24 2023, 15:18:16) [Clang 14.0.3 (clang-1403.0.22.14.1)] (/usr/local/Cellar/ansible/8.3.0/libexec/bin/python)
  jinja version = 3.1.2
  libyaml = True

• OCI Python SDK version:

# python -c "import oci;print(oci.__version__)"
2.110.1

• OCI Ansible Modules version:

# ansible-galaxy collection list oracle.oci

# /<Path>/ansible_collections
Collection Version
---------- -------
oracle.oci 4.30.0