[YUNIKORN-2074] Remove scheduler state machine

[craigcondit]

What is this PR for?

Replaces the scheduler state machine logic with much simpler sequential steps in scheduler.Run(). This should have no behavioral changes but dramatically simplifies startup logic.

What type of PR is it?

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

Todos

• - Task

What is the Jira issue?

https://issues.apache.org/jira/browse/YUNIKORN-2074

How should this be tested?

Screenshots (if appropriate)

Questions:

• - The licenses files need update.
• - There is breaking changes for older versions.
• - It needs documentation.

[codecov]

Codecov Report

Merging #700 (e7ca41e) into master (b4188fe) will decrease coverage by 0.27%.
The diff coverage is 60.52%.

@@            Coverage Diff             @@
##           master     #700      +/-   ##
==========================================
- Coverage   71.90%   71.64%   -0.27%     
==========================================
  Files          51       50       -1     
  Lines        8098     7955     -143     
==========================================
- Hits         5823     5699     -124     
+ Misses       2075     2058      -17     
+ Partials      200      198       -2     

Files	Coverage Δ
pkg/shim/scheduler.go	73.05% <60.52%> (-1.14%)	⬇️

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

[wilfred-s]

LGTM