RFR 8023197: Pre-configured command line options for keytool and jarsigner

[Wang Weijun]

Please review the code changes in

  http://cr.openjdk.java.net/~weijun/8023197/webrev.02

This enhancement allows you to put frequently used keytool/jarsigner options 
into a property file and use -conf to load it. Like this:

  # A Pre-configured options file
  keytool.all = -storepass:env PASS -keypass:env PASS -keystore 
${user.dir}/.p12 -storetype pkcs12
  keytool.genkeypair = -keyalg rsa -keysize 2048 -sigalg SHA256withRSA 
-validity 365

Thanks
Max