Rename JSDuck config to standard 'jsduck'

• Move configuration to /jsduck.json per standard.

• Move --processes=0 from maintenace script into config file.

• Use grunt-contrib-copy instead of a symlink for resources.

Also removed old JSDuck 4 logic.

Change-Id: Iaaaac50ee78dd9ff8f24f1ef3a3685ad51cf33b2
(cherry picked from commit 3bbd27aa4911e491a6e0838438e9bc03c9df22c6)