Add AppConfig provider for the parameters module #1084
Description
To fill the gap with Powertools for Python, we should add AppConfig as a source for parameters.
Python version: https://awslabs.github.io/aws-lambda-powertools-python/2.9.1/utilities/parameters/#appconfigprovider
In order to provide this, we can implement a new Provider (AppConfigProvider) extending the BaseProvider we already have.
Note that adding this implies to add a dependency to the AppConfig SDK, which will make the module heavier. Thinking about a v2, we could permit to choose only the required provider (and dependencies) to limit the size of the module.
Probably in v2, if we separate parameters in submodules and have one for AppConfig, it could also be used for Feature Flag module (if reuse is possible and makes sense).