add middleware and backup domains for query region

[lihsai0]

KODO-17792

[codecov]

Codecov Report

Merging #412 (889b1f1) into master (ba9cb83) will increase coverage by 0.74%.
The diff coverage is 90.86%.

Additional details and impacted files

@@            Coverage Diff             @@
##           master     #412      +/-   ##
==========================================
+ Coverage   85.46%   86.20%   +0.74%     
==========================================
  Files          16       22       +6     
  Lines        1452     1588     +136     
  Branches      334      357      +23     
==========================================
+ Hits         1241     1369     +128     
- Misses        211      219       +8     

Impacted Files	Coverage Δ
index.js	100.00% <ø> (ø)
qiniu/zone.js	82.22% <76.47%> (+0.40%)	⬆️
qiniu/httpc/middleware/base.js	85.71% <85.71%> (ø)
qiniu/httpc/middleware/retryDomains.js	87.17% <87.17%> (ø)
qiniu/httpc/responseWrapper.js	91.66% <91.66%> (ø)
qiniu/httpc/client.js	94.36% <94.36%> (ø)
qiniu/conf.js	100.00% <100.00%> (ø)
qiniu/httpc/middleware/index.js	100.00% <100.00%> (ø)
qiniu/httpc/middleware/ua.js	100.00% <100.00%> (ø)
qiniu/rpc.js	87.50% <100.00%> (+0.96%)	⬆️