feat: refactor sentinel, support cbRules, flowRules and systemRules

[sysulq]

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[codecov-commenter]

Codecov Report

Merging #366 (1d5160e) into master (4d33ced) will increase coverage by 1.47%.
The diff coverage is 63.44%.

@@            Coverage Diff             @@
##           master     #366      +/-   ##
==========================================
+ Coverage   36.45%   37.92%   +1.47%     
==========================================
  Files          82       87       +5     
  Lines        5262     5558     +296     
==========================================
+ Hits         1918     2108     +190     
- Misses       3226     3309      +83     
- Partials      118      141      +23     

Impacted Files	Coverage Δ
pkg/sentinel/context.go	0.00% <0.00%> (ø)
pkg/sentinel/sentinel.go	30.00% <30.00%> (ø)
pkg/sentinel/datasouce_etcd.go	48.00% <48.00%> (ø)
pkg/sentinel/config.go	72.38% <73.43%> (ø)
pkg/client/resty/resty.go	88.88% <81.25%> (-1.12%)	⬇️
pkg/sentinel/sentinel_circuitbreaker.go	100.00% <100.00%> (ø)
pkg/store/gorm/init.go	42.30% <0.00%> (+11.53%)	⬆️

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