[SCB-2234] configuration for instance properties should support placeholder

[wujimin]

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[codecov-io]

Codecov Report

Merging #2310 (3a4aa83) into master (8619d5c) will decrease coverage by 0.02%.
The diff coverage is 81.81%.

@@             Coverage Diff              @@
##             master    #2310      +/-   ##
============================================
- Coverage     79.27%   79.24%   -0.03%     
  Complexity     1369     1369              
============================================
  Files          1535     1535              
  Lines         41087    41092       +5     
  Branches       3466     3466              
============================================
- Hits          32572    32564       -8     
- Misses         7014     7025      +11     
- Partials       1501     1503       +2     

Impacted Files	Coverage Δ	Complexity Δ
...java/org/apache/servicecomb/zeroconfig/Config.java	0.00% <ø> (ø)	0.00 <0.00> (ø)
...java/org/apache/servicecomb/config/ConfigUtil.java	88.02% <50.00%> (-0.63%)	0.00 <0.00> (ø)
...apache/servicecomb/config/BootStrapProperties.java	66.12% <75.00%> (-2.73%)	0.00 <0.00> (ø)
...in/java/org/apache/servicecomb/core/SCBEngine.java	77.51% <100.00%> (+0.27%)	0.00 <0.00> (ø)
...ache/servicecomb/registry/RegistrationManager.java	88.27% <100.00%> (ø)	0.00 <0.00> (ø)
.../servicecomb/registry/discovery/DiscoveryTree.java	96.49% <0.00%> (-3.51%)	0.00% <0.00%> (ø%)
...mb/serviceregistry/client/http/RestClientUtil.java	75.70% <0.00%> (-1.87%)	0.00% <0.00%> (ø%)
...egistry/client/http/ServiceRegistryClientImpl.java	69.32% <0.00%> (-1.17%)	0.00% <0.00%> (ø%)

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