feat:sign image for helm chart

[liangyuanpeng]

What type of PR is this?

/kind feature

What this PR does / why we need it:

• sign image of helm chart
• renmae hack/package-helm-chart.sh to hack/helm-chart-package.sh for classify
• mv signImage() to util.sh and rename util::signImage()

Which issue(s) this PR fixes:
Part2 of #3435

Special notes for your reviewer:

Does this PR introduce a user-facing change?:

Use cosign to sign  Images of karmada helm chart and karmada operator helm chart.

[karmada-bot]

[APPROVALNOTIFIER] This PR is NOT APPROVED

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[codecov-commenter]

Codecov Report

All modified and coverable lines are covered by tests ✅

Comparison is base (961aa69) 52.84% compared to head (f3d8587) 52.84%.

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Additional details and impacted files

@@           Coverage Diff           @@
##           master    #3841   +/-   ##
=======================================
  Coverage   52.84%   52.84%           
=======================================
  Files         239      239           
  Lines       23558    23558           
=======================================
  Hits        12450    12450           
+ Misses      10432    10431    -1     
- Partials      676      677    +1     

Flag	Coverage Δ
unittests	52.84% <ø> (ø)

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see 2 files with indirect coverage changes

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[zishen]

good

[RainbowMango]

@liangyuanpeng sorry for the delay. I'm not sure if I have enough time for this month, busying with KubeCon stuff recently.

[liangyuanpeng]

@RainbowMango No worry, this is a low level issue. My talk of karmada for kubecon shanghai is missed and still wish you have fun 😄

[RainbowMango]

Oh, what a pity~

[RainbowMango]

Ask @zhzhuang-zju to take a look and help.