metrics: add storeID to metrics back

[rleungx]

What problem does this PR solve?

#1429 uses the address to replace storeID in metrics, but since pd-ctl uses storeID to execute the store related command, it's not convenient for us to trace the problem. Another problem is when a store becomes tombstone, and add it back with the same address, the reset metrics function will reset this address. So it is better to add storeID back.

What is changed and how it works?

This PR adds storeID to metrics back.

Check List

Tests

• Unit test

Related changes

• Need to update the tidb-ansible repository

[codecov-io]

Codecov Report

Merging #1506 into master will increase coverage by 0.05%.
The diff coverage is 85.34%.

@@            Coverage Diff             @@
##           master    #1506      +/-   ##
==========================================
+ Coverage   67.51%   67.56%   +0.05%     
==========================================
  Files         158      158              
  Lines       15550    15578      +28     
==========================================
+ Hits        10499    10526      +27     
+ Misses       4092     4090       -2     
- Partials      959      962       +3

Impacted Files	Coverage Δ
server/metrics.go	100% <ø> (ø)	⬆️
server/schedule/metrics.go	100% <ø> (ø)	⬆️
server/schedulers/metrics.go	100% <ø> (ø)	⬆️
server/schedule/filters.go	76.57% <100%> (+0.27%)	⬆️
server/store_statistics.go	85.08% <100%> (+0.13%)	⬆️
server/heartbeat_streams.go	75% <55.55%> (-0.52%)	⬇️
server/coordinator.go	84.58% <68.42%> (+0.24%)	⬆️
server/grpc_service.go	57.52% <75%> (-0.35%)	⬇️
server/schedulers/balance_region.go	82.45% <85.71%> (+1.14%)	⬆️
server/schedulers/balance_leader.go	96.22% <94.11%> (+0.43%)	⬆️
... and 9 more

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[siddontang]

so now we have both store address and ID in the metrics, right?

[rleungx]

@siddontang Right, it is more convenient for us to trace the problem.