Enhance GPU flavor scanning and update documentation

- Introduced SCAN_POOLS configuration to specify pools for GPU flavor scanning.
- Updated the `flavors` command to scan specified pools and list available GPU flavors based on `FLAVOR_PREFERENCE`.
- Revised CLI documentation to reflect changes in the `flavors` command behavior.
- Enhanced decision documentation to include details about GPU pool scanning.
- Updated setup instructions to guide users on selecting appropriate GPU pools.

tests/test_pools.py

@@ -0,0 +1,22 @@
+from gpu_rent.pools import PoolGpuOffer, format_pool_scan
+
+
+def test_format_pool_scan_recommends_first_hit():
+    from gpu_rent.inventory import FlavorInfo
+
+    offers = [
+        PoolGpuOffer(region="ru-7", multizone=False, gpu_labels_found=[], matched=[], gpu_types=[]),
+        PoolGpuOffer(
+            region="ru-6",
+            multizone=True,
+            gpu_labels_found=["4090-24", "4090-48"],
+            gpu_types=["4090", "H200"],
+            matched=[
+                FlavorInfo("1", "GL-4090", 4, 16384, False, {}, "4090-24"),
+            ],
+        ),
+    ]
+    text = "\n".join(format_pool_scan(offers, ("4090-24", "4090-48")))
+    assert "ru-6" in text and "multizone" in text
+    assert "типы:" in text
+    assert "рекомендация: OS_REGION_NAME=ru-6" in text