Remove RecursiveProxyModelBase #102

Job	Run time
build (ubuntu-latest, ci-dev-client-only-qt5, 5.15)	3m 32s
build (ubuntu-latest, ci-dev-client-only-qt6, 6.5.*, qtshadertools qtscxml)	4m 44s
build (ubuntu-latest, ci-dev-client-and-ui-qt5, 5.15)	5m 40s
build (ubuntu-latest, ci-dev-client-and-ui-qt6, 6.5.*)	7m 30s
build (windows-latest, ci-dev-client-only-qt5, 5.15)	4m 26s
build (windows-latest, ci-dev-client-only-qt6, 6.5.*, qtshadertools qtscxml)	6m 6s
build (windows-latest, ci-dev-client-and-ui-qt5, 5.15)	7m 27s
build (windows-latest, ci-dev-client-and-ui-qt6, 6.5.*)	10m 9s
build (macos-latest, ci-dev-client-only-qt5, 5.15)	5m 55s
build (macos-latest, ci-dev-client-only-qt6, 6.5.*, qtshadertools qtscxml)	5m 36s
build (macos-latest, ci-dev-client-and-ui-qt5, 5.15)	6m 45s
build (macos-latest, ci-dev-client-and-ui-qt6, 6.5.*)	8m 0s
	1h 15m 50s

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