feature(multi-bucket): add multi-bucket support to storage components

[jordanvn]

Description of changes

Changes:

• Adds optional property "bucket" to <StorageImage /> and <StorageManager />.
  • This property accepts the argument of either:
    • A string of the "friendly name" of the bucket
    • A StorageBucket object containing the bucket name generated on S3 and the region it exists in
  • If omitted, these storage components will use whichever bucket the user has designated as their "default" bucket in their configuration.

Issue #, if available

N/A

Description of how you validated changes

• [x] Functionality of the backend support of multiple buckets was validated
• [x] Example apps were modified to use multi-bucket setup
• [ ] Multi-bucket support was confirmed in example apps

Checklist

• [x] Have read the Pull Request Guidelines
• [x] PR description included
• [x] yarn test passes and tests are updated/added
• [x] PR title and commit messages follow conventional commit syntax
• [ ] If this change should result in a version bump, changeset added (This can be done after creating the PR.) This does not apply to changes made to docs, e2e, examples, or other private packages.

By submitting this pull request, I confirm that my contribution is made under the terms of the Apache 2.0 license.