feat: add folder menu registry for plugin menu extensions - #1782

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Include file: <QObject> not found. Please note: Cppcheck does not need standard library headers to get proper results.

Include file: <QHash> not found. Please note: Cppcheck does not need standard library headers to get proper results.

The function 'menuItems' is never used.

The function 'unregisterProvider' is never used.

The function 'registerProvider' is never used.

Condition 'm_providers.value(folderType)!=provider' is always false

Condition '!provider' is always false

Include file: <QSet> not found. Please note: Cppcheck does not need standard library headers to get proper results.

Include file: <QMetaMethod> not found. Please note: Cppcheck does not need standard library headers to get proper results.

Include file: <QCoreApplication> not found. Please note: Cppcheck does not need standard library headers to get proper results.