(change) Initialization of retrievers should also eventually call their specific initialization methods

[DeamonDev]

Motivation

I observed the flow of initializing of some retrievers may be not complete. When we call InitRetriever method to spawn
s3 retriever then we internally call

func createS3Retriever(c *retrieverconf.RetrieverConf, _ time.Duration) (retriever.Retriever, error) {
	awsConfig, err := awsConf.LoadDefaultConfig(context.Background())
	return &s3retrieverv2.Retriever{Bucket: c.Bucket, Item: c.Item, AwsConfig: &awsConfig}, err
}

But there is also initialization method for s3 retriever.

Requirements

Discussion whether we should call specific init methods here or not

[thomaspoignant]

@DeamonDev GOFF is actually supporting multiple interfaces as you see here.

Depending on which interface the retriever is using it will call the Init method of the retriever (see here).

The code snippet you've put in the issue is used only in the relay proxy, that force to use the AWS default locations for the authentication.
For the cli we should probably have the same mechanism because it is more secure than providing the secrets to the cli directly.

[DeamonDev]

Thanks for pointing this out. I added this additional init methods analogously to goff in #4025.