[issue-52] Add distribution publishing configuration

[vijikarthi]

Signed-off-by: Vijay Srinivasaraghavan vijayaraghavan.srinivasaraghavan@emc.com

Change log description

• added configurations to assemble artifacts for distribution

Purpose of the change Fixes https://github.com/pravega/hadoop-connectors/issues/52

What the code does

• added new build task to assemble release artifacts to a specific directory location

How to verify it run ./gradlew clean distribution and verify the release artifacts under $buildDir/distributions

[crazyzhou]

Closing stale PR