Add warnings regarding unsupported keys in optim config and OneCycleLR

[kingyiusuen]

What does this PR do?

Fixes #9630

• Added a warning when unsupported keys are found in a optimizer config dict.
• Added a warning when a OneCycleLR scheduler is used and "interval" is "epoch".

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[awaelchli]

LGTM
users may not know how to turn off the warning

[codecov]

Codecov Report

Merging #9666 (9f6d5a7) into master (4bebf82) will decrease coverage by 4%.
The diff coverage is 100%.

@@           Coverage Diff           @@
##           master   #9666    +/-   ##
=======================================
- Coverage      93%     89%    -4%     
=======================================
  Files         179     179            
  Lines       15305   15319    +14     
=======================================
- Hits        14197   13598   -599     
- Misses       1108    1721   +613