feat: add trainer configuration

[MIchaelFU0403]

Add trainer configuration

Description

Trainer is designed for training machine learning and ai models that support schedulers to make scheduling decision for each peer task.

Related Issue

Motivation and Context

Screenshots (if appropriate)

Types of changes

• Bug fix (non-breaking change which fixes an issue)
• New feature (non-breaking change which adds functionality)
• Breaking change (fix or feature that would cause existing functionality to change)
• Documentation Update (if none of the other choices apply)

Checklist

• My change requires a change to the documentation.
• I have updated the documentation accordingly.
• I have read the CONTRIBUTING document.
• I have added tests to cover my changes.

[codecov]

Codecov Report

Merging #2216 (90afcf0) into main (bcd992e) will increase coverage by 0.14%.
The diff coverage is 92.10%.

@@            Coverage Diff             @@
##             main    #2216      +/-   ##
==========================================
+ Coverage   49.47%   49.62%   +0.14%     
==========================================
  Files         145      146       +1     
  Lines       19429    19505      +76     
==========================================
+ Hits         9613     9679      +66     
- Misses       9224     9230       +6     
- Partials      592      596       +4     

Flag	Coverage Δ
Object-compatibility-e2etests	?
e2etests	?
unittests	49.62% <92.10%> (+0.14%)	⬆️

Flags with carried forward coverage won't be shown. Click here to find out more.

Impacted Files	Coverage Δ
trainer/config/config.go	92.10% <92.10%> (ø)

... and 2 files with indirect coverage changes

[gaius-qi]

LGTM