Remove faq for k8s multicluster rollout

[ffjlabo]

What this PR does / why we need it:

Currently, PIpeCD can't support the feature for now.

Which issue(s) this PR fixes:

Fixes #

Does this PR introduce a user-facing change?:

• How are users affected by this change:
• Is this breaking change:
• How to migrate (if breaking change):

[codecov[bot]]

Codecov Report

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

Project coverage is 22.78%. Comparing base (c0d5b79) to head (07369f1). Report is 5 commits behind head on master.

Additional details and impacted files

```diff @@ Coverage Diff @@ ## master #5153 +/- ## ========================================== - Coverage 22.79% 22.78% -0.01% ========================================== Files 412 412 Lines 43827 43827 ========================================== - Hits 9992 9988 -4 - Misses 33047 33050 +3 - Partials 788 789 +1 ```

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