feat: Implement resource quota validation for SparkConnect

[Denyme24]

Purpose of this PR

This PR adds resource quota validation support for SparkConnect to prevent silent pod failures and provide clear error messages to users when quota limits are exceeded.

fixes #2790

Proposed changes:

• Add validating admission webhook for SparkConnect to validate resource quotas at creation time
• Implement resource quota calculation logic that accounts for server pod + all executor pods
• Enhance SparkConnect controller to update status with quota validation errors
• Register SparkConnect webhook in operator startup to enable quota enforcement
• Add v1alpha1 scheme support to WebhookScheme for proper SparkConnect object handling

• SparkConnect creation is now rejected with clear error messages when it would exceed namespace resource quotas
• Status field shows detailed quota validation errors instead of remaining empty
• Behavior is now consistent with SparkApplication's resource quota enforcement

Change Category

• Bugfix (non-breaking change which fixes an issue)
• Feature (non-breaking change which adds functionality)
• Breaking change (fix or feature that could affect existing functionality)
• Documentation update

Rationale

Checklist

• I have conducted a self-review of my own code.
• I have updated documentation accordingly.
• I have added tests that prove my changes are effective or that my feature works.
• Existing unit tests pass locally with my changes.

Additional Notes

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[Denyme24]

hey @nabuskey @ImpSy, PTAL.

[Denyme24]

hey @ChenYi015 @Shekharrajak, could you please review these changes.
thank you.