VO2-WT Walkthrough of QSR 1.2 safety plan

VO2-WT Walkthrough of safety plan updates for QSR 1.2. See https://bugreports.qt.io/browse/QSR-663

Safety plan in the wiki: https://intranet.qt.io/display/QTRD/Qt+Safe+Renderer+Safety+Plan+1.2

All review comments will be available in this task.

The definition of done (DoD):

1) Document adheres to documentation guidelines in the Qt Safe Renderer 1.2 Safety Plan
2) The document has been verified according to Qt Safe Renderer 1.2 verification specification (see the document in Sharepoint: https://qtcompany.sharepoint.com/:w:/r/sites/QtQuality/_layouts/15/Doc.aspx?sourcedoc=%7B854D5752-AF13-4622-A835-0913E0FAA4A3%7D&file=Qt_Safe_Renderer_Verification_Specification.docx&action=default&mobileredirect=true)
3) The document has been approved
        * approval acknowledged by approved in corresponding Jira task
        * approval information added to document by owner or approver