Standardize the naming conventions for karmada system roles

[zhzhuang-zju]

What type of PR is this?
/kind cleanup

What this PR does / why we need it:
refer to #5793 (comment)

• standardize the naming of Karmada system roles by prefixing them with system:karmada
• rename label kubernetes.io/bootstrapping: rbac-defaults to karmada.io/bootstrapping: rbac-defaults
• remove annotation rbac.authorization.kubernetes.io/autoupdate: "true"
• standardize the group for karmada bootstrapping bearer tokens by prefixing them with system:bootstrappers:karmada

Which issue(s) this PR fixes:
Fixes #

Special notes for your reviewer:

Does this PR introduce a user-facing change?:

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Codecov Report

All modified and coverable lines are covered by tests ✅

Project coverage is 46.04%. Comparing base (7ac890f) to head (26103ec).

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Additional details and impacted files

@@           Coverage Diff           @@
##           master    #5837   +/-   ##
=======================================
  Coverage   46.03%   46.04%           
=======================================
  Files         660      660           
  Lines       53985    53985           
=======================================
+ Hits        24852    24857    +5     
+ Misses      27516    27513    -3     
+ Partials     1617     1615    -2     

Flag	Coverage Δ
unittests	46.04% <ø> (+<0.01%)	⬆️

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[zhzhuang-zju]

/assign @RainbowMango

[RainbowMango]

/lgtm
/approve

[karmada-bot]

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