feat(ws): add validation webhooks for Workspace and WorkspaceKind

[Adembc]

This PR makes the following changes:

• Re-add cert manager install, It was removed in this PR

Workspace Validations:

• Reject creation of Workspaces with invalid spec.kind (must reference an existing WorkspaceKind).

WorkspaceKind Validations:

• Reject updates to spec.podTemplate.options.imageConfig.values[].spec
• Reject updates to spec.podTemplate.options.podConfig.values[].spec
• Prevent cycles in options.
• Only allow removal of option IDs that are not in use.
• Ensure a default option exists.
• Ensure that ports in spec.podTemplate.options.imageConfig.values[].spec.ports[].port are unique.
• Ensure spec.podTemplate.extraEnv[].value is a valid Go template.

Tests:

• Add unit tests for validating Workspace creation.
• Add unit tests for validating WorkspaceKind creation.
• Add unit tests for validating updates to WorkspaceKind.

[Adembc]

@thesuperzapper I've added a commit to refactor the ValidateCreate and ValidateUpdate functions in the WorkspaceKind webhook. The refactoring focuses on extracting repeated code into reusable functions and reducing the number of loops to improve efficiency and readability

[thesuperzapper]

@Adembc thanks for your work on this and the rest of GSOC!

I did quite a bit of refactoring in the following commits:

• ce5ea50
• f6ca24b
• 4487a2c

The WorkspaceKind webhook needed a lot of work to make it behave correctly (and detect redirect cycles in a semi-efficient way), and I also made the tests specifically check for each kind of error and added some "success" cases, because otherwise everything might just be failing.

I think this PR should be ready for an initial merge now, there should only be two things left to have a fully working controller, I will raise issues so we can track that work publicly:

1. Implement the "culling controller"
2. Adding Istio VirtualService reconciliation to the workspace controller.

/lgtm
/approve

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