refactor: restructure Lighter SDK by removing deprecated Go files and enhancing Python documentation with new examples and models

docs/lighter/lighter-python-main/examples/margin_eth_20x_cross_http.py

@@ -0,0 +1,29 @@
+import asyncio
+from utils import default_example_setup
+
+
+async def main():
+    client, api_client, _ = default_example_setup()
+
+    # Note: the HTTP method `update_leverage` receives `leverage` as the argument,
+    # while the WS one that calls `sign_update_leverage` to get the TX to send it directly over WS
+    # receives `fraction` as the argument, which is 10_000 / leverage
+    # this was kept this way to not break backwards compatibility. Ideally, they would be consistent.
+
+    tx, tx_hash, err = await client.update_leverage(
+        market_index=0,
+        leverage=20,
+        margin_mode=client.CROSS_MARGIN_MODE
+    )
+
+    print(f"Update Leverage {tx=} {tx_hash=} {err=}")
+    if err is not None:
+        raise Exception(err)
+
+    await client.close()
+    await api_client.close()
+
+
+if __name__ == "__main__":
+    asyncio.run(main())
+