refactor wus-system to system-active with new polygon

active-crust/grid/features/grid-system-active.geojson

+{
+  "type": "Feature",
+  "id": 8130,
+  "geometry": {
+    "type": "Polygon",
+    "coordinates": [[
+      [-126.05, 50.05],
+      [-126.05, 23.95],
+      [ -98.65, 23.95],
+      [-102.35, 29.85],
+      [-104.50, 31.70],
+      [-105.35, 33.25],
+      [-105.55, 33.85],
+      [-105.25, 34.45],
+      [-105.30, 35.95],
+      [-105.17, 36.59],
+      [-105.12, 36.81],
+      [-104.60, 36.95],
+      [-104.50, 37.10],
+      [-105.10, 37.90],
+      [-104.80, 38.45],
+      [-105.40, 39.80],
+      [-106.00, 39.85],
+      [-106.50, 39.80],
+      [-107.00, 39.65],
+      [-107.50, 39.55],
+      [-108.00, 39.10],
+      [-108.20, 38.75],
+      [-108.25, 38.00],
+      [-108.20, 37.00],
+      [-107.45, 36.50],
+      [-107.45, 35.00],
+      [-108.00, 34.60],
+      [-109.00, 34.25],
+      [-110.00, 34.40],
+      [-111.00, 34.50],
+      [-112.30, 35.25],
+      [-112.30, 35.70],
+      [-112.30, 36.20],
+      [-112.45, 37.00],
+      [-112.25, 38.00],
+      [-111.35, 39.55],
+      [-110.20, 40.00],
+      [-110.75, 41.00],
+      [-110.50, 42.18],
+      [-110.50, 43.00],
+      [-110.05, 44.15],
+      [-109.90, 44.90],
+      [-110.00, 45.50],
+      [-110.35, 45.75],
+      [-110.50, 46.45],
+      [-110.60, 46.85],
+      [-112.20, 47.55],
+      [-113.35, 49.00],
+      [-114.10, 50.05],
+      [-126.05, 50.05]
+    ]]
+  },
+  "properties": {
+    "name": "WUS System Grid Region"
+  }
+}

active-crust/grid/system-active/branch-avg/rupture-sets.json

+[
+  {
+    "name": "WUS Branch Average",
+    "id": 8131,
+    "feature": 8130,
+    "mfd-tree": "system-active-mfd",
+    "grid-mfds": "branch-avg-grid.csv"
+  }
+]

active-crust/grid/system-active/mfd-map.json

+{
+  "system-active-mfd": [
+    {
+      "id": "M1",
+      "weight": 1.0,
+      "value": {
+        "type": "INCR",
+        "magnitudes": [
+          5.05, 5.15, 5.25, 5.35, 5.45, 5.55, 5.65, 5.75, 5.85, 5.95,
+          6.05, 6.15, 6.25, 6.35, 6.45, 6.55, 6.65, 6.75, 6.85, 6.95,
+          7.05, 7.15, 7.25, 7.35, 7.45, 7.55, 7.65, 7.75, 7.85, 7.95 ]
+      }
+    }
+  ]
+}

active-crust/grid/system-active/source-tree.json

+[
+  {
+    "id": "branch-avg",
+    "weight": 1.0
+  }
+]

active-crust/grid/system-active/tree-info.json

+{
+  "id": 8139,
+  "name": "WUS System Grid Sources"
+}