feat(ci): add scheduled oci integration-test workflows

[blackboxsw]

Proposed Commit Message

feat(ci): add scheduled oci integration-test workflows

Create oci workflow integration test coverage for Oracle on Ubuntu
Jammy, Noble, Resolute and Stonking scheduled twice-weekly:
 - Mon & Thu, cron '2 22 * * 1,4

Extend the shared 100-dispatch-common.yml workflow:
- add 'oci' to the workflow_dispatch platform choice list
- add two optional secrets PYCLOUDLIB_OCI_CONFIG_B64 / PYCLOUDLIB_OCI_KEY_B64 to workflow_call.secrets
- pass PYCLOUDLIB_OCI_CONFIG_FILE_PATH / PYCLOUDLIB_OCI_KEY_FILE_PATH to the Run integration Tests step env
- clean up the oci dir in the Clean pycloudlib step

Additional Context

Success run on individual oci creds: https://github.com/blackboxsw/cloud-init/actions/runs/30711239669

Test Steps

1. Can adapt this PR to run on your own remote:

sed -i 's/canonical\/cloud-init/YOUR_GHUSERNAME\/cloud-init/' .github/workflows/100-common-dispatch.yml
git commit -am 'WIP: adapt to run integration tests on my github remote'
git push YOUR_REMOTE THIS_BRANCH:main # --force to ensure github actions on your remote can be run directly from /github.com/YOUR_REMOTE/cloud-init/actions 

2. provide base64 encoded pycloudlib.toml with an [oci] section documenting your config

[oci]
config_path = "$OCI_CONFIG_FILE_PATH"
region = "us-...-1"
availability_domain = "qIZq:......."
compartment_id = "ocid1.compartment......."
public_key_path = "~/.ssh/cloudinit_id_rsa.pub"
vcn_name = "default"

3. Add action SECRETS to your remote to test workflow https://github.com/YOUR_REMOTE/cloud-init/settings/secrets/actions

• Create an oci config file via new API Keys from cloud.oracle.com
  PYCLOUDLIB_OCI_CONFIG_B64 # Copy value from: cat oci.config | base64 -w 0

• Grab private key pem from cloud.oracle.com
  PYCLOUDLIB_OCI_KEY_B64 # Copy value from: cat your-team-login-date*pem | base64 -w 0

• PYCLOUDLIB_TOML_B64 # copy value from cat pycloudlib.toml | base64 -w 0

SSH_PRIVATE_KEY # Copy shared CI private key used for all integration tests
SSH_PUBLIC_KEY # ditto public key

Merge recommendations

• Squash merge using "Proposed Commit Message"
• Rebase and merge unique commits. Requires commit messages per-commit each referencing the pull request number (#<PR_NUM>)