Decouple device parsing logic from Acc connector to Trainer

[kaushikb11]

What does this PR do?

Step towards simplifying the Accelerator Connector.

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[codecov]

Codecov Report

Merging #8180 (cf427d1) into master (bf54ac1) will decrease coverage by 0%.
The diff coverage is 100%.

@@          Coverage Diff           @@
##           master   #8180   +/-   ##
======================================
- Coverage      88%     88%   -0%     
======================================
  Files         212     212           
  Lines       13542   13547    +5     
======================================
- Hits        11958   11903   -55     
- Misses       1584    1644   +60     

[ethanwharris]

LGTM, small comment 😃

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