v1.15 add maintain job

[shichaoyuan]

Please provide issue(s) of this PR:
Fixes #

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• ApiServer
• Auth
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• Performance and Scalability
• Test and Release

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• Does not have any user-facing changes. This may include API changes, behavior changes, performance improvements, etc.

[codecov]

Codecov Report

Merging #1029 (c7488de) into release-v1.15.0 (d8108b7) will increase coverage by 0.05%.
The diff coverage is 43.90%.

@@                 Coverage Diff                 @@
##           release-v1.15.0    #1029      +/-   ##
===================================================
+ Coverage            57.75%   57.81%   +0.05%     
===================================================
  Files                  190      190              
  Lines                34381    34419      +38     
===================================================
+ Hits                 19858    19898      +40     
+ Misses               11933    11923      -10     
- Partials              2590     2598       +8     

Impacted Files	Coverage Δ
service/instance.go	63.14% <ø> (+1.29%)	⬆️
service/instance_authability.go	54.25% <ø> (+6.14%)	⬆️
store/mysql/maintain.go	46.97% <0.00%> (-4.12%)	⬇️
store/boltdb/maintain.go	69.67% <50.00%> (-11.10%)	⬇️
cache/circuitbreaker_config.go	68.06% <100.00%> (+0.13%)	⬆️
cache/faultdetect.go	65.74% <100.00%> (+2.01%)	⬆️

... and 5 files with indirect coverage changes

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