Add mes and mescc-tools-extra

mescc-tools-extra contains two important tools:
- cp
- chmod

mes first builds itself from a mes 0.21 seed as used by guix, and then
builds a mes 0.22 and then mes 0.22 using that created mes 0.22.

It does /not/ use bootstrap.sh as we don't have a proper shell at this
point, it has been manually adapted for kaem.

sysa/mes-0.22/lib/tests/scaffold/70-array-in-struct-init.stdout

@@ -0,0 +1,6 @@
+{10,{11,12,13}},
+{20,{21,22,0}},
+{30,{31,0,0}},
+{40,{41,0,0}},
+{0}
+};