server: add /debug/zip api to get useful debuginfo at once

[lysu]

What problem does this PR solve?

when we do troubleshooting often need multiple round-trips to get info from our custom.

to save time we need the ability to get more info at once, just curl or access

http://0.0.0.0:10080/debug/zip

What is changed and how it works?

get go pprof info in one file and maybe we can add more info in future, now after unzip we will got:

• heap pprof(after gc)
• mutex pprof
• cpu pprof (default 10s)
• full goroutine
• tidb config info
• tidb version info

Check List

Tests

• Manual test (add detailed scripts or steps below)

can be curl and unzip and be go pprof or cat without error

Code changes

• New code

Side effects

• N/A

Related changes

• Need to cherry-pick to the release 2.1

---

This change is 

[codecov]

Codecov Report

Merging #9651 into master will decrease coverage by 0.0651%.
The diff coverage is 0%.

@@               Coverage Diff                @@
##             master      #9651        +/-   ##
================================================
- Coverage   67.2409%   67.1757%   -0.0652%     
================================================
  Files           381        381                
  Lines         79874      79944        +70     
================================================
- Hits          53708      53703         -5     
- Misses        21381      21451        +70     
- Partials       4785       4790         +5

[jackysp]

Great!
Please add it to the doc file.

[jackysp]

LGTM

[jackysp]

PTAL @tiancaiamao

[tiancaiamao]

LGTM

[tiancaiamao]

/run-all-tests