Add ability to convert landmap to/from miz.

This PR adds utility functions that import/export landmap files to .miz
polygons. In addition to the unit test, this PR has been tested by
writing the Caucuses & Syria landmaps to a .miz file, loading the
generated .miz file back in and checking that the loaded landmap object
is identical to the original files.

tests/theater/test_landmap.py

@@ -0,0 +1,32 @@
+import os
+import pytest
+
+from shapely.geometry import MultiPolygon, Polygon
+
+from dcs.terrain.caucasus.caucasus import Caucasus
+from game.theater import landmap
+
+
+def test_miz() -> None:
+    """
+    Test miz generation and loading
+    """
+    test_map = landmap.Landmap(
+        inclusion_zones=MultiPolygon([Polygon([(0, 0), (0, 1), (1, 0)])]),
+        exclusion_zones=MultiPolygon([Polygon([(1, 1), (0, 1), (1, 0)])]),
+        sea_zones=MultiPolygon([Polygon([(0, 0), (0, 2), (1, 0)])]),
+    )
+    test_filename = "test.miz"
+    landmap.to_miz(test_map, Caucasus(), test_filename)
+    assert os.path.isfile("test.miz")
+    loaded_map = landmap.from_miz("test.miz")
+    assert test_map.inclusion_zones.equals_exact(
+        loaded_map.inclusion_zones, tolerance=1e-6
+    )
+    assert test_map.sea_zones.equals_exact(loaded_map.sea_zones, tolerance=1e-6)
+    assert test_map.exclusion_zones.equals_exact(
+        loaded_map.exclusion_zones, tolerance=1e-6
+    )
+
+    if os.path.isfile(test_filename):
+        os.remove(test_filename)