Move usage flag configuration to agenthealth extension

[jefchien]

Description of the issue

Currently, the mode/region_type flags are only getting configured on the cloudwatch and cloudwatchlogs output plugins. If neither of those are configured, then those two flags will not get set.

Description of changes

• Moves the configured flags to the agenthealth extension instead.
• Separates out the flag set from the stats provider.
• Fixes the local mode for the awscloudwatchlogs exporter.

License

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

Tests

Fixed the unit tests (particularly the sample config tests).

Requirements

Before commit the code, please do the following steps.

1. Run make fmt and make fmt-sh
2. Run make lint

[codecov-commenter]

Codecov Report

Attention: Patch coverage is 76.92308% with 3 lines in your changes are missing coverage. Please review.

Project coverage is 63.70%. Comparing base (96d4763) to head (8c07622).
Report is 504 commits behind head on main.

Files	Patch %	Lines
...lugins/processors/ec2tagger/ec2metadataprovider.go	33.33%	2 Missing ⚠️
cfg/aws/credentials.go	0.00%	1 Missing ⚠️

Additional details and impacted files

@@            Coverage Diff             @@
##             main    #1064      +/-   ##
==========================================
+ Coverage   57.58%   63.70%   +6.11%     
==========================================
  Files         370      364       -6     
  Lines       17548    18856    +1308     
==========================================
+ Hits        10105    12012    +1907     
+ Misses       6848     6214     -634     
- Partials      595      630      +35     

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