support external redis sentinel cluster

[jeremyxu2010]

Signed-off-by: Jeremy Xu jeremyxu2010@gmail.com

Support external redis sentinel cluster. #2885

[codecov]

Codecov Report

Merging #2886 into master will decrease coverage by 0.05%.
The diff coverage is 23.33%.

@@            Coverage Diff             @@
##           master    #2886      +/-   ##
==========================================
- Coverage   60.45%   60.39%   -0.06%     
==========================================
  Files         102      102              
  Lines        8001     8025      +24     
==========================================
+ Hits         4837     4847      +10     
- Misses       2517     2523       +6     
- Partials      647      655       +8

Flag	Coverage Δ
#linux	60.39% <23.33%> (-0.06%)	⬇️

Impacted Files	Coverage Δ
configuration/configuration.go	65.59% <ø> (ø)	⬆️
registry/handlers/app.go	47.9% <23.33%> (-0.27%)	⬇️

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[jeremyxu2010]

@caervs I tried many times to improve code coverage, but still failed. Can you review the PR and tell me how to improve code coverage in this scenario?

[dmcgowan]

Let's reassess this once we have a better way to make this plugable without adding new library dependencies