Improve paths validation and creation in certServiceClient, improve coverage

Add tests for path validation
Add tests for CsrConfigurationFactory
Ensure path from env can end with "/"
Ensure path built in file creator is not dependent on representation of root path

Issue-ID: AAF-996
Signed-off-by: Remigiusz Janeczek <remigiusz.janeczek@nokia.com>
Change-Id: I3d6a7f534d49ff64177917989727a7330e3f6869
6 files changed