Preview page Integration

• A new Previewer.page.js file should be created under the app/pages folder
• A new folder of graphql should be created under app folder
• A new file with name previewer.queries.js should be created under app/graphql folder
• This file should contain all the queries, mutations and subscriptions (schemas) needed for the Previewer page like:
  • e.g. getTemplates, getPagedPreviewerLink, updatePreviewerParameters,(examples can be found https://gitlab.coko.foundation/ketida/ketida/-/tree/master/packages/client/app/components/templates/src/queries and https://gitlab.coko.foundation/ketida/ketida/-/blob/master/packages/client/app/components/bookbuilder/src/queries/getPagedPreviewLink.js)
• Previewer.page.js should take advantage of useQuery and useMutation from @apollo/client for the execution of the above queries

Until the actual UI become ready the Previewer.page.js should return a dummy div. An example of a connected page is like here https://gitlab.coko.foundation/ketida/ketida/-/blob/websocket-locks/packages/client/app/components/wax/src/EditorPageWithData.js

Additionally, inside the connected layer Previewer.page.js the following handlers should be implemented: downloadPDFHandler and downloadEPUBHandler as well as a placeholder handler which will contain the logic of communicating with Lulu's system in order to post print jobs to their queue. These actions, will rely on axios as they will be calling REST endpoints thus outside the scope of graphql