Add webp thumbnail conversion task to optimize performance of fast scrolling (#172)

* Update readme

* Added webp to table and entity

* Added cronjob and sharp dependencies

* Added conversion of webp every 5 minutes and endpoint will now server webp image if exist

server/src/config/app.config.ts

@@ -17,5 +17,6 @@ export const immichAppConfig: ConfigModuleOptions = {
       then: Joi.string().optional().allow(null, ''),
       otherwise: Joi.string().required(),
     }),
+    VITE_SERVER_ENDPOINT: Joi.string().required(),
   }),
 };