MB-8972: implemented UI testing for settings tab

Change-Id: I27ff48c9c457959e8a069eaaaaaffddb36782e50
[alk@tut.by: removed non-semantic whitespace change]
Signed-off-by: Aliaksey Kandratsenka <alk@tut.by>
Reviewed-on: http://review.couchbase.org/29151
Reviewed-by: Aliaksey Kandratsenka <alkondratenko@gmail.com>
Tested-by: Aliaksey Kandratsenka <alkondratenko@gmail.com>