remove some warnings and inspection problems

src/main/java/fr/univamu/graph/UndirectedGraph.java

src/main/java/fr/univamu/graph/generators/ErdosRenyi.java

src/main/java/fr/univamu/graph/rootedtrees/NodeStats.java

src/main/java/fr/univamu/graph/rootedtrees/RootedTree.java

src/main/java/fr/univamu/graph/search/Search.java

src/main/java/fr/univamu/helpers/Iterations.java

.../java/fr/univamu/visualizer/RainbowDrawingParameters.java

src/main/java/module-info.java