refactor metrics let it initialize by configuration

[zhengyangyong]

Signed-off-by: zhengyangyong yangyong.zheng@qq.com

Ⅰ. Describe what this PR did

This pr refactor metrics in order to makes it works same as config or discovery loading mechanism.
now we can init it by config :

## metrics settings
metrics {
  registry-type = "compact"
  # multi exporters use comma divided
  exporter-list = "prometheus"
  exporter-prometheus-port = 9898
}

NOTICE: metrics is an optional feature so it will not configured by default, that means no metrics data is collecting and exporting by default even seata-metrics-all dependency had imported in server pom.

For more information, please refer to https://github.com/zhengyangyong/seata/blob/metrics_tc_improve/metrics/README.md

Ⅱ. Does this pull request fix one issue?

#384

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

Ⅳ. Describe how to verify it

https://seata.io/zh-cn/docs/ops/operation.html (need update later)

Ⅴ. Special notes for reviews

[codecov-io]

Codecov Report

Merging #1245 into develop will decrease coverage by 4.1%.
The diff coverage is 100%.

@@              Coverage Diff              @@
##             develop    #1245      +/-   ##
=============================================
- Coverage      49.47%   45.36%   -4.11%     
+ Complexity      1651     1511     -140     
=============================================
  Files            326      256      -70     
  Lines          11439    10354    -1085     
  Branches        1415     1339      -76     
=============================================
- Hits            5659     4697     -962     
+ Misses          5153     5073      -80     
+ Partials         627      584      -43

Impacted Files	Coverage Δ	Complexity Δ
...java/io/seata/server/metrics/MeterIdConstants.java	96.55% <ø> (ø)	1 <0> (ø)	⬇️
...ava/io/seata/server/metrics/MetricsSubscriber.java	73.52% <ø> (ø)	6 <0> (ø)	⬇️
...n/java/io/seata/server/metrics/MetricsManager.java	81.81% <100%> (ø)	5 <1> (ø)	⬇️
...java/io/seata/core/protocol/RegisterRMRequest.java	56.06% <0%> (-43.94%)	8% <0%> (+2%)
.../seata/core/protocol/AbstractIdentifyResponse.java	45.83% <0%> (-35.65%)	4% <0%> (ø)
.../io/seata/core/protocol/AbstractResultMessage.java	66.03% <0%> (-33.97%)	14% <0%> (+9%)
...rotocol/transaction/AbstractBranchEndResponse.java	65.62% <0%> (-22.84%)	10% <0%> (+5%)
...core/protocol/transaction/GlobalBeginResponse.java	77.77% <0%> (-22.23%)	8% <0%> (+2%)
...protocol/transaction/AbstractBranchEndRequest.java	68.31% <0%> (-16.54%)	14% <0%> (+7%)
...n/java/io/seata/core/protocol/AbstractMessage.java	15.25% <0%> (-6.18%)	5% <0%> (+3%)
... and 102 more

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[xingfudeshi]

@zhengyangyong Please resolve conflicting files.

[zhengyangyong]

Done

[CoffeeLatte007]

LGTM

[xingfudeshi]

LGTM

[slievrly]

LGTM