Add some South Atlantic naval assets (#23)

- Unit yamls for several ships and added some new ones to uk_1990.json
- 2 new layouts: Aircraft Carrier / LHA with Frigate escorts
- Add "HMS Invincible" as Control Point

resources/factions/uk_1990.json

@@ -48,6 +48,10 @@
     "Rapier"
   ],
   "naval_units": [
+    "P265 Dumbarton Castle",
+    "F72 Ariadne",
+    "F57 Andromeda",
+    "F12 Achilles",
     "FFG Oliver Hazard Perry",
     "DDG Arleigh Burke IIa",
     "CG Ticonderoga",