Option for an external webdriver

(still must be on port 4444)
Add build option --wd-server

To specify the host/port of an external
(already running) webdriver instance.
Add the "./Build test_tap" action which outputs plain TAP
use config file ngcp-schema/share/test.conf for testing

for NGCP::Schema
we activate this behaviour by setting the environment variable
NGCP_PANEL_CONFIG_LOCAL_SUFFIX to "testing" which is a feature
from Catalyst::Plugin::ConfigLoader
Use JUnit output by default with ./Build test

to not interfere with the JUnit output the panel output is redirected to a file
increase panel starting timeout

using ./Build test