Use AWSPlugin IAM credentials in other extension plugins

[chenqi0805]

Is your feature request related to a problem? Please describe.
Split from #3340 . AWS extension plugins usually requires IAM credentials, which might be pulled from AWSPlugin similar as pipeline plugin.

Describe the solution you'd like
Proper refactoring on ExtensionPlugin constructor and method

Describe alternatives you've considered (Optional)
A clear and concise description of any alternative solutions or features you've considered.

Additional context
Add any other context or screenshots about the feature request here.