SCB-988 Add loadbalancer in sc client

[little-cui]

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[codecov-io]

Codecov Report

Merging #479 into master will increase coverage by 0.04%.
The diff coverage is 94.11%.

@@            Coverage Diff             @@
##           master     #479      +/-   ##
==========================================
+ Coverage   60.24%   60.29%   +0.04%     
==========================================
  Files         156      157       +1     
  Lines       13484    13501      +17     
==========================================
+ Hits         8124     8140      +16     
- Misses       4779     4780       +1     
  Partials      581      581

Impacted Files	Coverage Δ
pkg/lb/roundrobin.go	94.11% <94.11%> (ø)
pkg/tlsutil/tlsutil.go	73.58% <0%> (-0.95%)	⬇️
server/broker/service.go	57.94% <0%> (+0.15%)	⬆️

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[coveralls]

Coverage increased (+0.03%) to 62.651% when pulling 57342eb on little-cui:lb into eb3aea0 on apache:master.

[asifdxtreme]

LGTM