[SUS-2443] Qt6 Migration
/its.cern.ch/jira/browse/SUS-2443
Submodules and .gitlab-ci.yml file will be adapted before merging.
For the Qt6 Migration I would like to do Reviews on SUGL, lgc-plugin and geode-plugin.
SUGL is the baseline for all plugins in his Merge request I want to focus on the PositionedQStringView class and changes to the Webengine.