Merge pull request #902 from cderici/model-name-on-2.9

#902

#### Description

Backports `model.name` from HEAD into 2.9. Gets this particular change from 55ea0e2 adds the name property into a Model object. Couldn't directly cherry pick because of the other stuff in the commit.

Fixes #893 

#### QA Steps

Also backports the integration test as well, so:

```
tox -e integration -- tests/integration/test_model.py::test_model_name
```

juju/model.py

@@ -1021,6 +1021,14 @@ async def get_info(self):
 
         return self.info
 
+    @property
+    def name(self):
+        """Return the name of this model
+        """
+        if self._info is None:
+            raise JujuError("Model is not connected")
+        return self._info.name
+
     @property
     def info(self):
         """Return the cached client.ModelInfo object for this Model.

tests/integration/test_model.py

@@ -21,6 +21,19 @@
 from ..utils import MB, GB, TESTS_DIR, OVERLAYS_DIR, SSH_KEY, INTEGRATION_TEST_DIR
 
 
+@base.bootstrapped
+@pytest.mark.asyncio
+async def test_model_name(event_loop):
+    model = Model()
+    with pytest.raises(JujuError):
+        model.name
+
+    async with base.CleanModel() as new_model:
+        await model.connect(new_model.name)
+        assert model.name == new_model.name
+        await model.disconnect()
+
+
 @base.bootstrapped
 @pytest.mark.asyncio
 async def test_deploy_local_bundle_dir(event_loop):