use official docker images for manual kubernetes deployment

[nobodyiam]

What's the purpose of this PR

Use official docker images for manual kubernetes deployment

Brief changelog

1. use official docker images
2. remove unnecessary docker build scripts
3. remove custom database scripts and let users use standard ones
4. use built-in default environment names instead of test-alpha and test-beta
5. adjust default replica to 2
6. remove init container check as there is no strict requirement of container startup sequence

Follow this checklist to help us incorporate your contribution quickly and easily:

• Read the Contributing Guide before making this pull request.
• Write a pull request description that is detailed enough to understand what the pull request does, how, and why.
• Write necessary unit tests to verify the code.
• Run mvn clean test to make sure this pull request doesn't break anything.
• Update the CHANGES log.

[codecov-commenter]

Codecov Report

Merging #3840 (8db281e) into master (b2d666f) will decrease coverage by 0.02%.
The diff coverage is n/a.

@@             Coverage Diff              @@
##             master    #3840      +/-   ##
============================================
- Coverage     50.15%   50.13%   -0.03%     
- Complexity     2465     2467       +2     
============================================
  Files           483      483              
  Lines         14921    14921              
  Branches       1520     1520              
============================================
- Hits           7484     7481       -3     
- Misses         6909     6913       +4     
+ Partials        528      527       -1     

Impacted Files	Coverage Δ
...mework/apollo/portal/component/PortalSettings.java	57.81% <0.00%> (-7.82%)	⬇️
.../apollo/internals/RemoteConfigLongPollService.java	77.10% <0.00%> (-0.61%)	⬇️
.../framework/apollo/spring/property/SpringValue.java	89.47% <0.00%> (+1.75%)	⬆️
...rk/apollo/spring/property/SpringValueRegistry.java	88.88% <0.00%> (+5.55%)	⬆️

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[JaredTan95]

LGTM