Add hwcloud provider and elb plugin

[gaopeiliang]

add hwcloud elb plugin work with ccm (https://github.com/kubernetes-sigs/cloud-provider-huaweicloud/tree/master) like aliyun slb

[codecov]

Codecov Report

All modified and coverable lines are covered by tests ✅

Project coverage is 38.49%. Comparing base (a1d0065) to head (6da6982).
Report is 18 commits behind head on master.

Additional details and impacted files

@@            Coverage Diff             @@
##           master     #201      +/-   ##
==========================================
- Coverage   39.56%   38.49%   -1.07%     
==========================================
  Files          33       39       +6     
  Lines        5366     6650    +1284     
==========================================
+ Hits         2123     2560     +437     
- Misses       3097     3911     +814     
- Partials      146      179      +33     

Flag	Coverage Δ
unittests	38.49% <100.00%> (-1.07%)	⬇️

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[chrisliu1995]

/lgtm