Remove android tutorials

[daniellevass]

I've removed the android tutorials.

I kept the heading and pointed to the new android tutorials for students who will go there first for the tutorials. However, I've hopefully made it explicit enough that it's only for special codebar android workshops. I can delete the entire heading if that'd be better?

[matyikriszta]

no, I think that's ok leaving the link in there with a caveat. @KimberleyCook what do you think? If you say it's fine I can merge.

[KimberleyCook]

@matyikriszta Looks good to me. Thanks for doing this @daniellevass :D :D

[matyikriszta]

merged, thanks @daniellevass 👍