Mention dependencies gcc and make

[klappradla]

I don't know whether this should be on the guides, but make and gcc are also required to compile scenic. I usually run my projects inside Docker and these packages are usually provided by the images, so I didn`t have them installed locally.

Originally posted by @LuisaAPF in #11 (comment)

With gcc and make being sort of "hidden" dependencies for Scenic, we should mention them somewhere. Either put a separate step into the guide checking for them, or link to a TROUBLESHOOTING.md file where we list things like that.

I'm currently leaning more towards the 2nd approach. It feel like it's easier to maintain and that it would also scale for other "eventual" troubles with the guide. gcc and make are from what I remember part of lot of distros already. Still, getting into the details of how install them on other platforms may be a bit hard to maintain and test for us. Let's see.

[jvf]

I am also in favour of a troubleshooting guide or section, it allows to keep the main instructions brief and to not cover every edge case. Still super useful to document the edge we encountered.