Pin plural name for all APIs to avoid unexpected change

[RainbowMango]

What type of PR is this?

/kind cleanup

What this PR does / why we need it: When the controller-tools generate the CRDs, it guesses the plural name by github.com/gobuffalo/flect if the plural name is not explicitly specified.

But the rule of generating plural names might change over different github.com/gobuffalo/flect versions. See https://github.com/kubernetes-sigs/controller-tools/pull/804#discussion_r1178098768 for an example.

So, this PR pin plural name for all APIs to avoid this unexpected change. (We don't depend on github.com/gobuffalo/flect, but the controller-tools reply on it. We might update controller-tools.) Which issue(s) this PR fixes: Fixes #

Special notes for your reviewer:

I'm trying to update the controller-tools but found the plural name of Karmada operator changed unexpectedly(see the fix at #4777), that reminds me we'd better pin the plural name.

Does this PR introduce a user-facing change?:

NONE

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Codecov Report

All modified and coverable lines are covered by tests :white_check_mark:

Project coverage is 51.78%. Comparing base (4e25482) to head (32a4076).

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Additional details and impacted files

```diff @@ Coverage Diff @@ ## master #4778 +/- ## ========================================== - Coverage 51.78% 51.78% -0.01% ========================================== Files 250 250 Lines 24989 24989 ========================================== - Hits 12941 12940 -1 - Misses 11339 11340 +1 Partials 709 709 ``` | [Flag](https://app.codecov.io/gh/karmada-io/karmada/pull/4778/flags?src=pr&el=flags&utm_medium=referral&utm_source=github&utm_content=comment&utm_campaign=pr+comments&utm_term=karmada-io) | Coverage Δ | | |---|---|---| | [unittests](https://app.codecov.io/gh/karmada-io/karmada/pull/4778/flags?src=pr&el=flag&utm_medium=referral&utm_source=github&utm_content=comment&utm_campaign=pr+comments&utm_term=karmada-io) | `51.78% <ø> (-0.01%)` | :arrow_down: | Flags with carried forward coverage won't be shown. [Click here](https://docs.codecov.io/docs/carryforward-flags?utm_medium=referral&utm_source=github&utm_content=comment&utm_campaign=pr+comments&utm_term=karmada-io#carryforward-flags-in-the-pull-request-comment) to find out more.

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