AwsConfigFile determines the correct location for the AWS config file.

PrintAwsConfig just prints what our new AWS config file block would look like.

UpdateAwsConfig updates our AWS config file, optionally presenting a diff for review or possibly making the change without prompting.

AwsCredentialsFile generates a new AWS credentials file or writes to STDOUT cfile is the path to the file to write to, or "" to write to stdout flags is the flags to pass to os.OpenFile creds is the list of credentials to write.