Add git submodules

Issue-Ref: 3835
Issue-Url: https://af3-developer.fortiss.org/issues/3835



Signed-off-by: Simon Barner <barner@fortiss.org>

.gitmodules

@@ -5,3 +5,4 @@
 [submodule "org.fortiss.af3.rcp.help/.settings"]
 	path = org.fortiss.af3.rcp.help/.settings
 	url = https://git.fortiss.org/af3/plugin-settings.git
+	branch = master