Improved test coverage for containerisation for 18.12

Includes commits from MR !22 (merged) and !24 (merged) pointed to 18.12:

Add tests:

• folder sharing (APERTIS-5706)
• device sharing (APERTIS-5707)
• connectivity profile (APERTIS-5713)
• AppArmor enforcement (APERTIS-5708)
• seccomp policy (APERTIS-5709)

Refactored check-tiny-containers script.

Created library with common functions for container management during the test.

Multiple improvements and fixes.