…ased CredentialProvider

For the credential resolver whereby the default ~/.aws/config and ~/.aws/credentials are evaluated for access credentials, the config variable 'use_aws_shared_config_files' is considered. However, for the process-based credential resolver, checking the same $HOME directory shared config files, it is not. This adds the same conditional check to ensure those files are not considered for either method where configuration is explicitly supplied indicating they should not be.

The default ordering is supposed to be:
1) env
2) web identity
3) profile config
4) Container/Instance

The process type is a relative new add. However, it was put below ECS. In the Java SDK, all profile processing (and case logic) is together in the search order. This makes that match.

See Also: https://github.com/aws/aws-sdk-java/blob/1.11.918/aws-java-sdk-core/src/main/java/com/amazonaws/auth/profile/ProfilesConfigFile.java#L207-L216

The default ordering is supposed to be:
1) env
2) web identity
3) profile config
4) Container/Instance

ECS deployments and instance profiles are easily detectable via an environment variable. If the environment variable is present, add the ECS provider to the chain; otherwise, add the instance profile provider.

See Also: https://github.com/aws/aws-sdk-java/blob/1.11.918/aws-java-sdk-core/src/main/java/com/amazonaws/auth/EC2ContainerCredentialsProviderWrapper.java#L58-L64

Comment stanza to match up with the terminology used throughout the code.