Create generic component accepting any EditorToolbar and Editor

[natterstefan]

Previously the EditorImage accepted any <Toolbar /> and <Editor /> component. They were rendered and connected with the onChange logic of the <LovelyEditor />.

We should add a generic component again so that one could easily add new Editors by simply adding them to the config like:

const blocksConfig = [
  {
    component: EditorGeneric,
    blockConfig: {
      component: CustomEditor,
      toolbar: CustomToolbar
    }
  }
]