Improve stability of scripts #4

[dboltovskyi]

This PR is [ready] for review.

Summary

Various fixes related to scripts which improve stability on a high loads.

ATF version

develop

Changelog

Enhancements

• added delay to disconnect function(s)
• added delay to connect function for WSS connection
• improved stability of Ignition Off sequence
• improved stability of some Policy scripts:
  • moved app registration to separate test step
  • added missing expectation on OnHMIStatus(FULL) in ActivateAppInSpecificLevel() function
  • reworked script to get rid of Unpin() function

Bug Fixes

• [Bug Fix Info]

CLA

• I have signed the CLA