RFR: JDK-8136777: Introduce bundle targets

[Erik Joelsson]

Hello,

This change introduces bundle targets for the OpenJDK build, which 
creates the same tar.gz and zip bundles as the full OracleJDK build does 
today. The motivation for this is to have one place where this happens, 
in a part of the build that is always being built by all our configurations.

This adds a new top level target all-bundles (or just bundles for 
short). There are also sub targets product-bundles, test-bundles and 
docs-bundles.

The Jib profiles have been updated to use the bundle targets as defaults.

Bug: https://bugs.openjdk.java.net/browse/JDK-8136777
Webrev: http://cr.openjdk.java.net/~erikj/8136777/webrev.01/

/Erik