feature: add apollo configuration namespace.

[objcoding]

Ⅰ. Describe what this PR did

Ⅱ. Does this pull request fix one issue?

fixes #1555

Ⅲ. Why don't you add test cases (unit test/integration test)?

Ⅳ. Describe how to verify it

Ⅴ. Special notes for reviews

[codecov-io]

Codecov Report

Merging #2086 into develop will decrease coverage by 0.02%.
The diff coverage is 11.11%.

@@              Coverage Diff              @@
##             develop    #2086      +/-   ##
=============================================
- Coverage      53.13%   53.11%   -0.03%     
  Complexity      2513     2513              
=============================================
  Files            485      485              
  Lines          15364    15355       -9     
  Branches        1771     1771              
=============================================
- Hits            8164     8156       -8     
  Misses          6413     6413              
+ Partials         787      786       -1

Impacted Files	Coverage Δ	Complexity Δ
...eata/server/session/db/DataBaseSessionManager.java	35% <ø> (+1.12%)	12 <0> (ø)	⬇️
...ta/spring/boot/autoconfigure/StarterConstants.java	97.36% <ø> (-0.41%)	1 <0> (ø)
...gure/provider/SpringBootConfigurationProvider.java	33.33% <0%> (ø)	9 <0> (ø)	⬇️
...o/seata/server/coordinator/DefaultCoordinator.java	49.8% <50%> (ø)	30 <0> (ø)	⬇️
...very/registry/zk/ZookeeperRegisterServiceImpl.java	62.29% <0%> (-0.82%)	24% <0%> (ø)

[slievrly]

Is ConfigApolloProperties missing the namespace field?

[objcoding]

Is ConfigApolloProperties missing the namespace field?

resolved.

[slievrly]

LGTM

[helloworlde]

LGTM

[zjinlei]

LGTM