support metrics for tc server

[zhengyangyong]

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

Ⅰ. Describe what this PR did

make tc support metrics and add default prometheus publisher

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

[zhengyangyong]

Metrics is record by MetricsSubscriber that listening Transaction Status Changed events from EventBus
Event Bus Mechanism PR : #768

[codecov-io]

Codecov Report

Merging #1236 into develop will increase coverage by 0.39%.
The diff coverage is 82.66%.

@@              Coverage Diff              @@
##             develop    #1236      +/-   ##
=============================================
+ Coverage      44.96%   45.36%   +0.39%     
- Complexity      1488     1511      +23     
=============================================
  Files            253      256       +3     
  Lines          10279    10354      +75     
  Branches        1337     1338       +1     
=============================================
+ Hits            4622     4697      +75     
- Misses          5069     5073       +4     
+ Partials         588      584       -4

Impacted Files	Coverage Δ	Complexity Δ
server/src/main/java/io/seata/server/Server.java	0% <0%> (ø)	0 <0> (ø)	⬇️
...ava/io/seata/server/metrics/MetricsSubscriber.java	73.52% <73.52%> (ø)	6 <6> (?)
...n/java/io/seata/server/metrics/MetricsManager.java	81.81% <81.81%> (ø)	5 <5> (?)
...java/io/seata/server/metrics/MeterIdConstants.java	96.55% <96.55%> (ø)	1 <1> (?)
...server/store/file/FileTransactionStoreManager.java	45.99% <0%> (-1.05%)	19% <0%> (ø)
...very/registry/zk/ZookeeperRegisterServiceImpl.java	63.77% <0%> (-0.79%)	24% <0%> (ø)
...o/seata/server/coordinator/DefaultCoordinator.java	55.15% <0%> (+3.6%)	26% <0%> (+3%)	⬆️
... and 1 more

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[slievrly]

In the next version，I hope to add a Mertic configuration node and load the SPI through the configuration in the configuration file, such as which type of exporter to load.

[zhengyangyong]

Sounds good, I will try it later

[slievrly]

function valid

[slievrly]

LGTM

[xingfudeshi]

LGTM.