RFR: JDK-8246627: Consolidate app image bundlers

[Alexey Semenyuk]

Please review fix [2] for jpackage bug [1].

Move duplicated functionality from LinuxAppBundler, MacAppBundler and 
WinAppBundler classes in the base class.

[2] webrev is on top of [3] webrev.

- Alexey

[1] https://bugs.openjdk.java.net/browse/JDK-8246627

[2] http://cr.openjdk.java.net/~asemenyuk/8246627/webrev.00

[3] http://cr.openjdk.java.net/~asemenyuk/8246624/webrev.00