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/logging/logger.go

@@ -0,0 +1,82 @@
+package logging
+
+import (
+	"context"
+	"io"
+	"log"
+)
+
+// Classification is the type of the log entry's classification name.
+type Classification string
+
+// Set of standard classifications that can be used by clients and middleware
+const (
+	Warn  Classification = "WARN"
+	Debug Classification = "DEBUG"
+)
+
+// Logger is an interface for logging entries at certain classifications.
+type Logger interface {
+	// Logf is expected to support the standard fmt package "verbs".
+	Logf(classification Classification, format string, v ...interface{})
+}
+
+// LoggerFunc is a wrapper around a function to satisfy the Logger interface.
+type LoggerFunc func(classification Classification, format string, v ...interface{})
+
+// Logf delegates the logging request to the wrapped function.
+func (f LoggerFunc) Logf(classification Classification, format string, v ...interface{}) {
+	f(classification, format, v...)
+}
+
+// ContextLogger is an optional interface a Logger implementation may expose that provides
+// the ability to create context aware log entries.
+type ContextLogger interface {
+	WithContext(context.Context) Logger
+}
+
+// WithContext will pass the provided context to logger if it implements the ContextLogger interface and return the resulting
+// logger. Otherwise the logger will be returned as is. As a special case if a nil logger is provided, a Nop logger will
+// be returned to the caller.
+func WithContext(ctx context.Context, logger Logger) Logger {
+	if logger == nil {
+		return Nop{}
+	}
+
+	cl, ok := logger.(ContextLogger)
+	if !ok {
+		return logger
+	}
+
+	return cl.WithContext(ctx)
+}
+
+// Nop is a Logger implementation that simply does not perform any logging.
+type Nop struct{}
+
+// Logf simply returns without performing any action
+func (n Nop) Logf(Classification, string, ...interface{}) {
+	return
+}
+
+// StandardLogger is a Logger implementation that wraps the standard library logger, and delegates logging to it's
+// Printf method.
+type StandardLogger struct {
+	Logger *log.Logger
+}
+
+// Logf logs the given classification and message to the underlying logger.
+func (s StandardLogger) Logf(classification Classification, format string, v ...interface{}) {
+	if len(classification) != 0 {
+		format = string(classification) + " " + format
+	}
+
+	s.Logger.Printf(format, v...)
+}
+
+// NewStandardLogger returns a new StandardLogger
+func NewStandardLogger(writer io.Writer) *StandardLogger {
+	return &StandardLogger{
+		Logger: log.New(writer, "SDK ", log.LstdFlags),
+	}
+}