pd-web: remove

[HunDunDM]

Signed-off-by: hundundm hundundm@gmail.com

What problem does this PR solve?

Removed pd-web and keyvisualService. They will be replaced by Dashboard.

What is changed and how it works?

Check List

[lhy1024]

LGTM

[codecov-io]

Codecov Report

Merging #2121 into master will increase coverage by 0.06%.
The diff coverage is n/a.

@@            Coverage Diff             @@
##           master    #2121      +/-   ##
==========================================
+ Coverage   76.82%   76.89%   +0.06%     
==========================================
  Files         194      192       -2     
  Lines       19990    19899      -91     
==========================================
- Hits        15358    15302      -56     
+ Misses       3482     3453      -29     
+ Partials     1150     1144       -6

Impacted Files	Coverage Δ
tests/cluster.go	85.76% <ø> (-0.06%)	⬇️
server/server.go	80.25% <ø> (-0.32%)	⬇️
pkg/apiutil/serverapi/middleware.go	73.03% <0%> (-8.99%)	⬇️
server/schedulers/base_scheduler.go	60.86% <0%> (-8.7%)	⬇️
server/tso/tso.go	81.75% <0%> (-2.19%)	⬇️
server/grpc_service.go	57.29% <0%> (-1.08%)	⬇️
server/schedulers/adjacent_region.go	75.4% <0%> (-1.07%)	⬇️
pkg/btree/btree.go	87.65% <0%> (+0.8%)	⬆️
client/base_client.go	86.2% <0%> (+1.37%)	⬆️
... and 4 more

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[lhy1024]

/merge

[sre-bot]

/run-all-tests

[sre-bot]

cherry pick to release-3.1 in PR #2122