QtHelpDocumentation - Share a single StandardDocumentationView instance

For each documentation page a new StandardDocumentationView was constructed
including a new QwebEngineView and related classes and the whole setup and
initilization process was done again. It is much more efficient to just load()
the new page.
Status Job ID Name Coverage
failed #41045
linux kf5-qt5 qt5.12

Name Stage Failure
linux kf5-qt5 qt5.12 Build There has been a timeout failure or the job got stuck. Check your timeout limits or try again
No job log