Add custom common metric tag feature

[zwmagic]

What type of PR is this?

Feature

What this PR does / why we need it?

Add custom common metric tag feature

Which issue(s) this PR fixes？

Fixes #1707

Does this PR introduce a user-facing change?

Yes. We will update user guide at sermant.io.

Checklist

• Make sure there is a GitHub_issue related with this PR before you start working on it.
• Make sure you have squashed your change to one single commit.
• GitHub Actions works fine in this PR.

[codecov]

Codecov Report

Attention: Patch coverage is 0% with 54 lines in your changes missing coverage. Please review.

Files with missing lines	Patch %	Lines
...ore/service/metric/entity/MetricCommonTagEnum.java	0.00%	25 Missing ⚠️
.../sermant/implement/service/metric/MeterMetric.java	0.00%	15 Missing ⚠️
...rmant/core/service/metric/config/MetricConfig.java	0.00%	9 Missing ⚠️
.../java/io/sermant/core/service/metric/api/Tags.java	0.00%	3 Missing ⚠️
...o/sermant/router/common/metric/MetricsManager.java	0.00%	2 Missing ⚠️

Flag	Coverage Δ	Complexity Δ
unittests	43.78% <0.00%> (-0.08%)	181.00 <0.00> (ø)

Flags with carried forward coverage won't be shown. Click here to find out more.

Files with missing lines	Coverage Δ	Complexity Δ
...ermant/router/common/constants/RouterConstant.java	100.00% <ø> (ø)	0.00 <0.00> (ø)
...o/sermant/router/common/metric/MetricsManager.java	27.77% <0.00%> (ø)	0.00 <0.00> (ø)
.../java/io/sermant/core/service/metric/api/Tags.java	0.00% <0.00%> (ø)	0.00 <0.00> (ø)
...rmant/core/service/metric/config/MetricConfig.java	0.00% <0.00%> (ø)	0.00 <0.00> (ø)
.../sermant/implement/service/metric/MeterMetric.java	0.00% <0.00%> (ø)	0.00 <0.00> (ø)
...ore/service/metric/entity/MetricCommonTagEnum.java	0.00% <0.00%> (ø)	0.00 <0.00> (?)

... and 2 files with indirect coverage changes