FELIX-3989 Add support for determining code coverage with integration testcases

Adding config for JoCoCo maven plugin to capture code coverage report. Following command would enable coverage

mvn clean install -Pide,felix,coverage

For now the coverage is bit low hence not enabling the check by default.

git-svn-id: https://svn.apache.org/repos/asf/felix/trunk@1459658 13f79535-47bb-0310-9956-ffa450edef68