Create setup and initial runtime checkers

[aemous]

Description of changes:

• Create code architecture for migration readiness feature.
• Implement ecr get-login breaking change checker.
• Implement hidden aliases breaking change checker.
• Implement URL in params breaking change checker.
• Add new-change file.

By submitting this pull request, I confirm that you can use, modify, copy, and redistribute this contribution, under the terms of your choice.

[AndrewAsseily]

Looks like we have a couple of CI tests that need attention

[codecov-commenter]

Codecov Report

❌ Patch coverage is 52.00000% with 12 lines in your changes missing coverage. Please review.
⚠️ Please upload report for BASE (debug-migration@d6685a8). Learn more about missing BASE report.

Files with missing lines	Patch %	Lines
awscli/customizations/globalargs.py	29.41%	12 Missing ⚠️

Additional details and impacted files

@@                Coverage Diff                 @@
##             debug-migration    #9703   +/-   ##
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  Coverage                   ?   93.27%           
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  Files                      ?      209           
  Lines                      ?    16821           
  Branches                   ?        0           
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  Hits                       ?    15689           
  Misses                     ?     1132           
  Partials                   ?        0           

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