Include information on how to login when using DEMO mode

[vildead]

People accessing demo instance of DAISY do not know how to login.

The "About" page has the information.

• include the informaiton about how to login on the landing login page

(btw, it used to be there 🤔 )

[neoflex]

From what I am seeing, it's still there in the login.html template but within a %comment% block.
Maybe we used to edit the file manually on the demo instance to remove the {% comment %}.

[vildead]

@neoflex nice! I have updated our demo instance

How much work would be needed to do this automatically (e.g. using DEMO_MODE variable)?