RFR (JDK11/NIO) 8201276: (fs) Add methods to Files for reading/writing a string from/to a file

Hi, We're looking into adding methods to Files to read a file into a String/write a String to a file. Below is the current proposal. Please review. JBS: https://bugs.openjdk.java.net/browse/JDK-8201276 webrev: http://cr.openjdk.java.net/~joehw/jdk11/8201276/webrev/ specdiff: http://cr.openjdk.java.net/~joehw/jdk11/8201276/specdiff/java/nio/file/Files.html Thanks, Joe