http-server: add deleteTidbCluster api

[z2665]

What problem does this PR solve?

add delete TidbCluster api for http-server

What is changed and how does it work?

Code changes

• Has Go code change
• Has CI related scripts change

Tests

• Unit test
• E2E test
• Manual test
• No code

1. use CreateCluster http api to create a tidb cluster
   see example/create-cluster.json

2. check tidb running success
   

3. call DeleteCluster http api to delete the tidb cluster

{
  "success": true
}

check namespace,secret,tidbmonitor and tidbInitializers all be deleted

Side effects

• Breaking backward compatibility
• Other side effects:

Related changes

• Need to cherry-pick to the release branch
• Need to update the documentation

Release Notes

Please refer to Release Notes Language Style Guide before writing the release note.

[ti-chi-bot]

[APPROVALNOTIFIER] This PR is NOT APPROVED

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[sre-bot]

All committers have signed the CLA.

[ti-chi-bot]

Welcome @z2665! It looks like this is your first PR to pingcap/tidb-operator 🎉

[codecov-commenter]

Codecov Report

Merging #5371 (d9b4c69) into master (0cd81d1) will increase coverage by 0.00%.
The diff coverage is n/a.

Additional details and impacted files

@@           Coverage Diff           @@
##           master    #5371   +/-   ##
=======================================
  Coverage   61.59%   61.60%           
=======================================
  Files         228      228           
  Lines       28866    28866           
=======================================
+ Hits        17780    17782    +2     
+ Misses       9342     9341    -1     
+ Partials     1744     1743    -1     

Flag	Coverage Δ
unittest	61.60% <ø> (+<0.01%)	⬆️