Some of the gst-plugins-good modules were missing to setup a cam for some basic scenarios/tutorials. I added it so they'll be added to the default build set.

The description is not indented after line breaks. All other
information, i.e., the dependencies and SRCURI, are indented with
four spaces after line breaks. Shell scripts are indented with
multiples of four spaces.

In recipes-ros, I located and checked for tabulators and spacing
with these bash commands:

egrep '^ [^ ]+' . --exclude *.patch -R
egrep '^  [^ ]+' . --exclude *.patch -R
egrep '^   [^ ]+' . --exclude *.patch -R
egrep '^    [ ]+[^ ]+' . --exclude *.patch -R

While going through the recipes and manually improving the layout,
I also adjusted the descriptions to use maximal 100 characters
per line.