Remove page from index but not deleting its content (#9884)

This is a temporary step on #9884. With the assistant people won't read
this before choosing their media so it doesn't make sense to keep it
here and it's also outdated. So let's hide it for the time being.

Conflicts:
	wiki/src/doc/first_steps.index.mdwn

wiki/src/doc/first_steps.index.mdwn

@@ -6,7 +6,6 @@ instructions, provided as a fallback.</p>
 
 </div>
 
-  - [[!traillink Choosing_between_burning_a_DVD_and_installing_onto_a_USB_stick_or_SD_card|first_steps/media]]
   - [[!traillink Start_Tails|first_steps/start_tails]]
   - [[!traillink Startup_options|first_steps/startup_options]]
     - [[!traillink Administration_password|first_steps/startup_options/administration_password]]