buildkite currently reads secrets from the s3 secrets bucket into env vars for use by the pipeline. these secrets were copied into aws secretsmanager and this PR updates the pipeline so it uses the seek-oss/aws-sm plugin to read the secrets from aws secretsmanager for the https://buildkite.com/redpanda/deployment-automation pipeline. there is no functionality change because the env vars are kept the same name and values.
fixes https://redpandadata.atlassian.net/browse/PESDLC-1526
buildkite currently reads secrets from the s3 secrets bucket into env vars for use by the pipeline. these secrets were copied into aws secretsmanager and this PR updates the pipeline so it uses the seek-oss/aws-sm plugin to read the secrets from aws secretsmanager for the https://buildkite.com/redpanda/deployment-automation pipeline. there is no functionality change because the env vars are kept the same name and values.