Added debian/tests for running the didcot tests post build.

scripts for running the installed tests and didcot sample client
added under debian/tests which can be run with autopkgtest
utility

[smcv: remove trailing whitespace]

Signed-off-by: Rohan Madgula <Rohan.Madgula@in.bosch.com>
Reviewed-by: Simon McVittie <simon.mcvittie@collabora.co.uk>
Reviewed-by: Philip Withnall <philip.withnall@collabora.co.uk>
Differential Revision: https://phabricator.apertis.org/D4152