Support to Specify Extra Volumes and Volume Mounts for Karmada API Server Component

[jabellard]

What type of PR is this?

/kind feature

What this PR does / why we need it:

Today, when creating a Karmada instance to be managed by the Karmada operator, it's possible to specify extra args for the control plane components. However, it's not possible to specify extra volumes and volume mounts. This feature request is for providing the ability to specify extra volumes and volume mounts for the Karmada components.

Why is this needed:
At Bloomberg, we're currently building a managed Karmada platform and want to use the Karmada operator to manage the entire lifecycle of managed Karmada instances. We have tenants who have requirements such as the following:

• Ability to configure custom AuthN webhook
• Ability to configure encryption at rest

Given that it's already possible to specify extra args for components like the API server, having the ability to also specify extra volumes and volume mounts will enable those use cases.

Which issue(s) this PR fixes:
Fixes #5272

Special notes for your reviewer:

Does this PR introduce a user-facing change?:

When creating a Karmada instance to be managed by the Karmada operator, it's now possible to optionally specify extra volumes and volume mounts via the `extraVolumes` and `extraVolumemounts` flags, respectively, for the Karmada API server component.

[codecov-commenter]

⚠️ Please install the to ensure uploads and comments are reliably processed by Codecov.

Codecov Report

Attention: Patch coverage is 0% with 10 lines in your changes missing coverage. Please review.

Project coverage is 33.86%. Comparing base (54b90a2) to head (c45b817).
Report is 38 commits behind head on master.

Files with missing lines	Patch %	Lines
operator/pkg/util/patcher/pather.go	0.00%	8 Missing ⚠️
operator/pkg/controlplane/apiserver/apiserver.go	0.00%	2 Missing ⚠️

❗ Your organization needs to install the Codecov GitHub app to enable full functionality.

Additional details and impacted files

@@            Coverage Diff             @@
##           master    #5509      +/-   ##
==========================================
+ Coverage   32.32%   33.86%   +1.53%     
==========================================
  Files         643      643              
  Lines       44445    44509      +64     
==========================================
+ Hits        14368    15071     +703     
+ Misses      28985    28288     -697     
- Partials     1092     1150      +58     

Flag	Coverage Δ
unittests	33.86% <0.00%> (+1.53%)	⬆️

Flags with carried forward coverage won't be shown. Click here to find out more.

☔ View full report in Codecov by Sentry.
📢 Have feedback on the report? Share it here.

[RainbowMango]

Generally looks good to me, just give another look at the field names that I mentioned on #5276 (comment).

[jabellard]

Generally looks good to me, just give another look at the field names that I mentioned on #5276 (comment).

Just pushed some changes to address.

[RainbowMango]

/lgtm
/approve

[karmada-bot]

[APPROVALNOTIFIER] This PR is APPROVED

This pull-request has been approved by: RainbowMango

The full list of commands accepted by this bot can be found here.

The pull request process is described here

Needs approval from an approver in each of these files:

• charts/OWNERS [RainbowMango]
• operator/OWNERS [RainbowMango]
• operator/pkg/apis/OWNERS [RainbowMango]

Approvers can indicate their approval by writing /approve in a comment
Approvers can cancel approval by writing /approve cancel in a comment