chore: ensure we can deploy multiple releases in separate namespaces

[hazzadous]

This is partially to ensure we can run tests in clean envs, but is also
relevant to uses e.g. wanting to run prod and staging in the same
cluster.

Previously ClusterRoles and ClusterRoleBindings for the
clickhouse-operator were not unique, this uses the namespace to correct
that.

Description

Type of change

• Breaking change (fix or feature that would cause existing functionality to not work as expected)
• Bug fix (non-breaking change which fixes an issue)
• New feature (non-breaking change which adds functionality)

How has this been tested?

Checklist

• I have commented my code, particularly in hard-to-understand areas
• I have made corresponding changes to the documentation
• I have added tests that prove my fix is effective or that my feature works

[guidoiaquinti]

This PR ended up being more than a couple of changes. Here's a list of what has been done:

• refactor the current pytest parallelism as each test is now independent from others
• made clusterrole and clusterrolebinding coming from the clickhouse-operator unique across the namespace
• added in conftest logic to automatically wipe both k8s and helm before the start of each test
• minor fixes to black/isort/flake8 config
• disabled few flaky/broken tests (like clickhouse sharding, clickhouse backup, and Job migrate - CH multishard/replica provision race condition #462). I will fix those in a follow up PR but there's no point to block the pipeline for those

[posthog-bot]

We probably forgot to bump the chart with this merge. No worries head over to https://github.com/PostHog/charts-clickhouse/actions/workflows/bump-version-workflow-dispatch.yaml to trigger the chart update.