feat(dex): dex backend storage adapter implementation

[kengou]

Description

Implements:

• Resolves feature-flags with dex storage selection from a ConfigMap
• Dex backend storage adapter interface to support kubernetes or postgres
• idproxy and Organization Reconciler uses the storage adapter interface

Additionally implements #798 partially -

• If dex storage backend is kubernetes then Dex Custom Resources are created in the organization's namespace

What type of PR is this? (check all applicable)

• 🍕 Feature
• 🐛 Bug Fix
• 📝 Documentation Update
• 🎨 Style
• 🧑‍💻 Code Refactor
• 🔥 Performance Improvements
• ✅ Test
• 🤖 Build
• 🔁 CI
• 📦 Chore (Release)
• ⏩ Revert

Related Tickets & Documents

• Closes [FEAT] - Dex IDP Persistence with DB #738
• Related [FEAT] - Refactor DEX Controller #798

Added tests?

• 👍 yes
• 🙅 no, because they aren't needed
• 🙋 no, because I need help
• Separate ticket for tests # (issue/pr)

Added to documentation?

• 📜 README.md
• 🤝 Documentation pages updated
• 🙅 no documentation needed
• (if applicable) generated OpenAPI docs for CRD changes

Checklist

• My code follows the style guidelines of this project
• I have performed a self-review of my code
• I have commented my code, particularly in hard-to-understand areas
• My changes generate no new warnings
• New and existing unit tests pass locally with my changes

[abhijith-darshan]

@IvoGoman @kengou - Please review from scratch as the implementation has been re-written

Implements:

• Resolves feature-flags with dex storage selection from a ConfigMap
• Dex backend storage adapter interface to support kubernetes or postgres
• idproxy and Organization Reconciler uses the storage adapter interface
• organization controller will not try to Own dex CRs if the storage is postgres, which should allow running both postgres and kubernetes storage backends in the cluster

Additionally implements #798 -

• If dex storage backend is kubernetes then Dex Custom Resources are created in the organization's namespace
• OAuth2Client credentials secret is created in the organization's namespace following the pattern org-name-dex-secrets
• generates a deterministic client secret using hmac sha256 from clientID and secretKey + truncated to 32 characters (so as to consistently generate the same credential on every reconciliation)

TODO -

• We need to wrap environment variables in manager deployment with if postgres enabled and not have a static injection of postgres vars (currently e2e tests and helm lint fail because of that)
• for [FEAT] - Refactor DEX Controller #798 we need to early exit (requeue?) if the organization namespace is not active
• E2E tests for kubernetes and Postgres should be implemented