chore: use processedOptions

[CorentinDoue]

What did you implement:

Closes #833

Use processed options as suggested by @medikoo in serverless/serverless#9452 to improve the support for non-AWS providers

How did you implement it:

The raw options are now overridden by the processed options from serverless.processedInput.options during the initialize hook. (The first to be called at runtime)

How can we verify it:

Example with the command sls invoke local -f myFunctionName on GCP.
Before:

After:

I also tested it on an existing AWS project to check it broke nothing.

Todos:

• Write tests
• Write documentation
• Fix linting errors
• Make sure code coverage hasn't dropped
• Provide verification config / commands / resources
• Enable "Allow edits from maintainers" for this PR
• Update the messages below

Is this ready for review?: YES
Is it a breaking change?: NO

[j0k3r]

This looks ok to me, thanks for the contribution @CorentinDoue.
Can you see how to fix the serverless v1 build?

[CorentinDoue]

Can you see how to fix the serverless v1 build

I think serverless.processedInput does not exist with serverless v1. I will add an if to handle the retrocompatibility

[j0k3r]

Thanks!