[ISSUE-48] [Feature] Init Kubernetes operator directory

[jerqi]

What changes were proposed in this pull request?

To solve issue #48, First step. we add Kubernetes operator profile and directory. We add two scripts build-operator.sh and test-operator.sh. We can use these scripts to build and test our operator. When we use the command mvn compile -Pkubernetes, we can build the operator. When we use the command mvn test -Pkubernetes, we can test the operator.

Why are the changes needed?

We hope use Kubernetes to deploy Uniffle.

Does this PR introduce any user-facing change?

No

How was this patch tested?

No need.

[codecov-commenter]

Codecov Report

Merging #75 (1db4b57) into master (aa18be0) will decrease coverage by 0.02%.
The diff coverage is n/a.

@@             Coverage Diff              @@
##             master      #75      +/-   ##
============================================
- Coverage     56.39%   56.36%   -0.03%     
+ Complexity     1173     1171       -2     
============================================
  Files           149      149              
  Lines          7953     7953              
  Branches        761      761              
============================================
- Hits           4485     4483       -2     
- Misses         3226     3227       +1     
- Partials        242      243       +1     

Impacted Files	Coverage Δ
...e/uniffle/server/storage/SingleStorageManager.java	65.57% <0.00%> (-1.64%)	⬇️
.../apache/uniffle/coordinator/ClientConfManager.java	91.54% <0.00%> (-1.41%)	⬇️

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[wangao1236]

Thanks, I'll submit some PRs about dockerfile and operator of Uniffe.

[frankliee]

We can add a markdown file in doc directory to put its user guide.

[jerqi]

We can add a markdown file in doc directory to put its user guide.

When we finish the issue, we add the complete doc.

[colinmjj]

+1， LGTM