feat(registry/zk):url encode zkpath

[xujianhai666]

What this PR does:
be consistent with java impl, support url encoder for zkpath

[flycash]

I had checked codes using the zkPath. It seems that we don't need to decode the zkPath when we get the zkPath. Right?

[xujianhai666]

I had checked codes using the zkPath. It seems that we don't need to decode the zkPath when we get the zkPath. Right?

@flycash yes, just for zk registry

[codecov-io]

Codecov Report

Merging #283 into develop will increase coverage by 0.81%.
The diff coverage is 100%.

@@             Coverage Diff             @@
##           develop     #283      +/-   ##
===========================================
+ Coverage    65.52%   66.34%   +0.81%     
===========================================
  Files          111      111              
  Lines         7063     7065       +2     
===========================================
+ Hits          4628     4687      +59     
+ Misses        1978     1919      -59     
- Partials       457      459       +2

Impacted Files	Coverage Δ
registry/zookeeper/registry.go	55.39% <100%> (+0.32%)	⬆️
cluster/cluster_impl/failback_cluster_invoker.go	80.64% <0%> (+2.15%)	⬆️
protocol/dubbo/readwriter.go	70.37% <0%> (+2.46%)	⬆️
config_center/apollo/impl.go	87.01% <0%> (+2.59%)	⬆️
protocol/dubbo/codec.go	82.35% <0%> (+5.88%)	⬆️
protocol/dubbo/listener.go	61.9% <0%> (+10.71%)	⬆️
protocol/dubbo/pool.go	73.6% <0%> (+15.73%)	⬆️

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[zouyx]

I had checked codes using the zkPath too. we use zkPath to registry and get children node,so it seems that no need to decode.

[hxmhlt]

LGTM

[fangyincheng]

LGTM

[hxmhlt]

I checked java version. There is method named 'encoded' in URL.java and it called by ZookeeperRegistry for zkPath encode. Though I have not received any issue about this problem...Maybe it is encoded by zk golang client.

[xujianhai666]

I had checked codes using the zkPath too. we use zkPath to registry and get children node,so it seems that no need to decode.

@zouyx for consistent with java impl. Besides, grpc need this decode method to resolve "$" for inner class