Add support for HTTPS in SDC sanity/uiSanity tests

Add support for HTTPS in SDC sanity/uiSanity tests

New variable: SDC_TEST_HTTPS

Adjusted robot test too and fixed bad naming there - it was not
the SDC BE container but SDC FE.

For this change to work the upstream change in SDC has to be merged
too - or use this only with a local repo and with some proper setup.

+ Added quotes around shell variables

Issue-ID: SDC-2564

Signed-off-by: Petr Ospalý <p.ospaly@partner.samsung.com>
Change-Id: I3db9f2e1c22a539df3b6c356bd91f67f0328cbd7
Signed-off-by: Petr Ospalý <p.ospaly@partner.samsung.com>