[Web] Relevant Error Message + Guidance/Other links

- This is a private project, but the error message is not accurate (e.g. it should be: please ensure you have the right log in as this is a private project)

- Even when logged in correctly, this is a locked topic, and hence the return message should be (e.g. this topic is currently being locked until you have complete the relevant topic).

- Links to go to the home page (app.gametize.com), or to go to the project page should be there. Please ensure this for all error pages.