rbd: add aws-sts-metdata encryption type

With Amazon STS and kubernetes cluster is configured with
OIDC identity provider, credentials to access Amazon KMS
can be fetched using oidc-token(serviceaccount token).
Each tenant/namespace needs to create a secret with aws region,
role and CMK ARN.
Ceph-CSI will assume the given role with oidc token and access
aws KMS, with given CMK to encrypt/decrypt DEK which will stored
in the image metdata.

Refer: https://docs.aws.amazon.com/STS/latest/APIReference/welcome.html
Resolves: #2879

Signed-off-by: Rakshith R <rar@redhat.com>

vendor/github.com/aws/smithy-go/.travis.yml

@@ -0,0 +1,28 @@
+language: go
+sudo: true
+dist: bionic
+
+branches:
+  only:
+    - main
+
+os:
+  - linux
+  - osx
+  # Travis doesn't work with windows and Go tip
+  #- windows
+
+go:
+  - tip
+
+matrix:
+  allow_failures:
+    - go: tip
+
+before_install:
+  - if [ "$TRAVIS_OS_NAME" = "windows" ]; then choco install make; fi
+  - (cd /tmp/; go get golang.org/x/lint/golint)
+
+script:
+  - make go test -v ./...;
+