Fixes Related To AWS STS (in BlockStoreS3 And add_external_connection)

[shirady]

Explain the changes

1. In test_store_validity add the condition related to AWS STS as it appears in all other methods in the class.
2. In _delete_past_versions has a condition related to AWS so I added AWSSTS.
3. In add_external_connection add the type AWSSTS in a condition (which I thought was missing).

Issues: Fixed #xxx / Gap #xxx

1. Without the change in test_store_validity you could see in noobaa-core logs:

[WARN] core.agent.block_store_services.block_store_s3:: unexpected error (code=ExpiredToken) from deleteObject during test. ignoring..

Note: to see it live I changed the defaultSTSCredsValidity to 900 (minimum possible) and waited 15 minutes after the creation of the aws-sts backingstore.

Testing Instructions:

1. Create AWS STS Setup on Minikube (the guide will be in the operator repo, meanwhile this is the PR #Doc | Create AWS STS Setup on Minikube Dev Guide noobaa-operator#1244.
2. Build the image and deploy noobaa on MInikube (see guide).
   Note: nb is an alias that runs the local operator from build/_output/bin (alias created by devenv).
3. Create backingstore:
   nb backingstore create aws-sts-s3 <backingstore-name> -n <your-namespace>
4. Create bucket class:
   nb bucketclass create placement-bucketclass <bucketclass-name> --backingstores=<backingstore-name> -n <your-namespace>
5. Create OBC:
   nb obc create <obc-name> --bucketclass=<bucket-class-name> -n <your-namespace>
6. Using por-forward (due to using MacOS):
7. kubectl port-forward -n <your-namespace> service/s3 12443:443
8. Create the alias from the OBC creation output:
   alias s3-nb-user-1='AWS_SECRET_ACCESS_KEY=<paste-here> AWS_ACCESS_KEY_ID=<paste-here> aws --no-verify-ssl --endpoint-url https://localhost:12443'
9. Set higher debug level:
   nb system set-debug-level 3 -n <your-namespace>
10. Put an object
    s3-nb-user-1 s3api put-object --bucket <obc-bucket-name> --key <key-name> --body <path-to-file>
11. Get the object
    s3-nb-user-1 s3api get-object --bucket <obc-bucket-name> --key <key-name>

• Doc added/updated
• Tests added