Summary:
Earlier we used to have IAM roles attached to YBA and transferred generated credentials to
DB nodes for S3 based backup/restore. This PR adds the ability to use IAM role attached on the DB
node itself to carry out backup and restore. Note that this does not mean YAB does not need IAM, it
still needs it for validations/deletion etc

The feature is backward compatible and does not break existing users who only have IAm role attached
to YBA. It is controlled by a runtime feature flag: `yb.backup.s3.use_db_nodes_iam_role_for_backup`

As part of this change, also upgraded the YBC client and server version to 2.2.0.0-b10 which has the
ability to perform backup/restore using IAM role attached to DB node: https://github.com/yugabyte/ybc/pull/172

Test Plan: Verified backup/restore with IAM role attached to DB nodes.

Reviewers: anijhawan, kkg, sneelakantan

Reviewed By: anijhawan

Subscribers: yugaware

Differential Revision: https://phorge.dev.yugabyte.com/D40142