test: Use git repo in TestApp, test git remote existence.

Signed-off-by: Blaž Hrastnik <blaz.hrast@gmail.com>
test: TestResource should check for presence of ENV vars.

Signed-off-by: Blaž Hrastnik <blaz.hrast@gmail.com>
test: TestCluster validates against the config file as well.

Signed-off-by: Blaž Hrastnik <blaz.hrast@gmail.com>