Java API Improvements

[netbeans at post.cz]

In context: 
https://mail.openjdk.java.net/pipermail/jdk-dev/2020-April/004240.html

Improvement String:

Instead of: 

public static boolean isNotNullAndBlank(String value) 
public static boolean isNotNullAndEmpty(String value) 

in case of adding "unless" (Stream; see link above):

public static boolean isNullOrBlank(String value) 
public static boolean isNullOrEmpty(String value) 


Improvement CharSequence: //if below ones are added then isNullOrBlank and 
isNullOrEmpty could goes there

public default isEmpty();
public default isBlank();