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):

[Warashi]

👍🏻

[codecov]

Codecov Report

All modified and coverable lines are covered by tests ✅

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

Additional details and impacted files

@@            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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[khanhtc1202]

Good bye and see you later 👋