First attempt at modularization

todolist/core/src/main/java/module-info.java

...ist/core/src/main/java/todolist/json/TodoPersistence.java

...ain/java/todolist/json/internal/TodoItemDeserializer.java

.../main/java/todolist/json/internal/TodoItemSerializer.java

...ain/java/todolist/json/internal/TodoListDeserializer.java

.../main/java/todolist/json/internal/TodoListSerializer.java

...in/java/todolist/json/internal/TodoModelDeserializer.java

...main/java/todolist/json/internal/TodoModelSerializer.java

...core/src/main/java/todolist/json/internal/TodoModule.java

...list/core/src/test/java/todolist/json/TodoModuleTest.java

todolist/fxui/src/main/java/module-info.java

...fxui/src/main/java/todolist/ui/RemoteTodoModelAccess.java

todolist/fxutil/src/main/java/module-info.java

todolist/rest/pom.xml

todolist/rest/src/main/java/module-info.java

...a/todolist/restserver/TodoModuleObjectMapperProvider.java

...st/src/test/java/todolist/restserver/TodoServiceTest.java

...list/springboot/restserver/src/main/java/module-info.java

.../todolist/springboot/restserver/TodoModelApplication.java

...olist/springboot/restserver/TodoModelApplicationTest.java