[YUNIKORN-1273] Add configurable option to have unique application ids in a namespace

[mitdesai]

What is this PR for?

Ability to configure autogenerated application ids. Currently, if the app id is not specified, yunikorn generates the application id with the name 'yunikorn-<name_space>-autogen' and all the pods with no application id are bundled under that name. This change adds an option to have unique auto-generated names. Appends pod uid after the namespace name to make it unique.

First time? Check out the contributing guide - http://yunikorn.apache.org/community/how_to_contribute
Successfully ran these commands in k8shim
make license-check
make lint
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What type of PR is it?

• - Bug Fix
• - Improvement
• - Feature
• - Documentation
• - Hot Fix
• - Refactoring

Todos

• - Task

What is the Jira issue?

• Open an issue on Jira https://issues.apache.org/jira/browse/YUNIKORN/1273
• https://issues.apache.org/jira/browse/YUNIKORN-1273

How should this be tested?

Screenshots (if appropriate)

Questions:

• [NO] - The licenses files need update.
• [NO] - There is breaking changes for older versions.
• [NO] - It needs documentation.

[wilfred-s]

Linter issues on comments, and two other minor comment nits

[codecov]

Codecov Report

Merging #594 (df70048) into master (2d91d01) will increase coverage by 0.23%.
The diff coverage is 100.00%.

@@            Coverage Diff             @@
##           master     #594      +/-   ##
==========================================
+ Coverage   69.95%   70.18%   +0.23%     
==========================================
  Files          47       47              
  Lines        7938     7950      +12     
==========================================
+ Hits         5553     5580      +27     
+ Misses       2177     2164      -13     
+ Partials      208      206       -2     

Impacted Files	Coverage Δ
pkg/admission/admission_controller.go	65.93% <100.00%> (-0.27%)	⬇️
pkg/admission/conf/am_conf.go	72.10% <100.00%> (+6.31%)	⬆️
pkg/admission/util.go	95.83% <100.00%> (+1.23%)	⬆️

... and 1 file with indirect coverage changes

📣 We’re building smart automated test selection to slash your CI/CD build times. Learn more

[mitdesai]

Codecov Report

Merging #594 (0f9aed1) into master (2d91d01) will decrease coverage by 0.01%.
The diff coverage is 80.95%.

❗ Current head 0f9aed1 differs from pull request most recent head df70048. Consider uploading reports for the commit df70048 to get more accurate results

@@            Coverage Diff             @@
##           master     #594      +/-   ##
==========================================
- Coverage   69.95%   69.94%   -0.01%     
==========================================
  Files          47       47              
  Lines        7938     7950      +12     
==========================================
+ Hits         5553     5561       +8     
- Misses       2177     2181       +4     
  Partials      208      208              

Impacted Files Coverage Δ
pkg/admission/conf/am_conf.go 64.80% <20.00%> (-0.99%) ⬇️
pkg/admission/admission_controller.go 65.93% <100.00%> (-0.27%) ⬇️
pkg/admission/util.go 95.83% <100.00%> (+1.23%) ⬆️
📣 We’re building smart automated test selection to slash your CI/CD build times. Learn more

1. Added tests for am_conf.go
2. admission_controller.go had a function moved to utils.go hence the difference in the covered lines.

[wilfred-s]

LGTM