enable ceph-csi integration

[kwmonroe]

Overview

Enable Ceph CSI integration.

Rationale

We're recommending ceph as the storage solution when using Canonical K8s as the backing cloud for juju add-k8s. This PR provides the integration needed by the ceph-csi subordinate charm.

Juju Events Changes

Adds a new relation-changed observation for ceph-k8s-info.

[github-actions[bot]]

Test coverage for 4de2c96d272940613af05b3450de3ee9f9b2738c

coverage-report: install_deps /home/runner/work/k8s-operator/k8s-operator/charms/worker/k8s> python -I -m pip install 'coverage[toml]'
coverage-report: commands[0] /home/runner/work/k8s-operator/k8s-operator/charms/worker/k8s> coverage report
Name                                    Stmts   Miss  Cover
-----------------------------------------------------------
lib/charms/k8s/v0/k8sd_api_manager.py     265     26    90%
src/charm.py                              442    231    48%
src/containerd.py                         140     16    89%
src/cos_integration.py                     33     12    64%
src/reschedule.py                          77      4    95%
src/snap.py                                79      3    96%
src/token_distributor.py                  165     92    44%
-----------------------------------------------------------
TOTAL                                    1201    384    68%
  coverage-report: OK (1.21=setup[1.03]+cmd[0.18] seconds)
  congratulations :) (1.26 seconds)

Static code analysis report

Run started:2024-10-30 12:00:56.488120

Test results:
    No issues identified.

Code scanned:
    Total lines of code: 2714
    Total lines skipped (#nosec): 14
    Total potential issues skipped due to specifically being disabled (e.g., #nosec BXXX): 0

Run metrics:
    Total issues (by severity):
        Undefined: 0
        Low: 0
        Medium: 0
        High: 0
    Total issues (by confidence):
        Undefined: 0
        Low: 0
        Medium: 0
        High: 0
Files skipped (0):

[addyess]

@mateoflorido can you take one final look here?

[addyess]

LGTM! Could you please create a follow up card to add more robust integration testing around this feature?

Done