feat: support the use of ciphertext passwords in yml.

[CorvusYe]

Support for #298

Developers can create a custom decoder that implements the interface PasswordDecoder

For example:

@Component
public class Base64PasswordDecoder implements PasswordDecoder {

  @Override
  public String decode(String password) {
    return new String(Base64.getDecoder().decode(password));
  }

}

nebula:
  username: root
  password: bmVidWxh # actual password is: nebula

Tip:

At this stage, it is not supported to use @Value to inject additional attributes.
现阶段 不 支持使用 @Value 注入额外属性。

PR type:

• new feat