sitl config: put model name first

Github constructs the workflow names from the 
matrix configurations. Having latitude and longitude
in the fist columns makes these names rather cryptic.

.github/workflows/sitl_tests.yml

@@ -15,10 +15,10 @@ jobs:
       fail-fast: false
       matrix:
         config:
-          - {latitude:  "59.617693", longitude: "-151.145316", altitude:  "48", build_type: "RelWithDebInfo",   model: "iris"          } # Alaska
-          - {latitude: "-38.071235", longitude:  "145.281220", altitude:  "31", build_type: "AddressSanitizer", model: "standard_vtol" } # Australia
-          - {latitude:  "29.660316", longitude:  "-82.316658", altitude:  "30", build_type: "RelWithDebInfo",   model: "tailsitter"    } # Florida
-          - {latitude:  "47.397742", longitude:    "8.545594", altitude: "488", build_type: "Coverage",         model: "standard_vtol" } # Zurich
+          - {model: "iris",          latitude:  "59.617693", longitude: "-151.145316", altitude:  "48", build_type: "RelWithDebInfo" } # Alaska
+          - {model: "standard_vtol", latitude: "-38.071235", longitude:  "145.281220", altitude:  "31", build_type: "AddressSanitizer" } # Australia
+          - {model: "tailsitter" ,   latitude:  "29.660316", longitude:  "-82.316658", altitude:  "30", build_type: "RelWithDebInfo" } # Florida
+          - {model: "standard_vtol", latitude:  "47.397742", longitude:    "8.545594", altitude: "488", build_type: "Coverage" } # Zurich
 
     container:
       image: px4io/px4-dev-simulation-focal:2021-09-08