RFR: JDK-8231282: Revisit --linux-deb-copyright option

[Alexey Semenyuk]

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

This is a fix for the JDK-8200758-branch branch of the open sandbox 
repository (jpackage).

This fix:

- remove --linux-deb-copyright option.
- add tests to verify that placing copyright template in custom resource 
dir provides the same functionality as the use of --linux-deb-copyright 
option.
- adjusted test helper classes to save from writing explicit code to 
rethrow checked exceptions as RuntimeException.

Baseline for the fix is [3].

[1] https://bugs.openjdk.java.net/browse/JDK-8231277

[2] http://cr.openjdk.java.net/~asemenyuk/8231282/webrev.00/

[3] http://cr.openjdk.java.net/~asemenyuk/8231279/webrev.01/