feat: adjust Column, Schema and Table to changes in Row (#216)

### Summary of Changes

* In `Column`:
  * Rename `count` to `n_rows` and make it a property

* In `Schema`:
  * Rename `get_column_names` to `column_names` and make it a property
  * Rename `get_type_of_column` to `get_column_type`

* In `Table`:
  * Rename `count_columns` to `n_columns` and make it a property
  * Rename `count_rows` to `n_rows` and make it a property
  * Rename `get_type_of_column` to `get_column_type`
* Remove `row count` from `summary` since it's the same for all columns
anyway

src/safeds/data/tabular/containers/_column.py

@@ -93,6 +93,18 @@ def name(self) -> str:
         """
         return self._name
 
+    @property
+    def n_rows(self) -> int:
+        """
+        Return the number of elements in the column.
+
+        Returns
+        -------
+        n_rows : int
+            The number of elements.
+        """
+        return len(self._data)
+
     @property
     def type(self) -> ColumnType:
         """
@@ -148,17 +160,6 @@ def get_value(self, index: int) -> Any:
     # Information
     # ------------------------------------------------------------------------------------------------------------------
 
-    def count(self) -> int:
-        """
-        Return the number of elements in the column.
-
-        Returns
-        -------
-        count : int
-            The number of elements.
-        """
-        return len(self._data)
-
     def all(self, predicate: Callable[[Any], bool]) -> bool:
         """
         Check if all values have a given property.

src/safeds/data/tabular/containers/_row.py

@@ -300,7 +300,7 @@ def column_names(self) -> list[str]:
         >>> row.column_names
         ['a', 'b']
         """
-        return self._schema.get_column_names()
+        return self._schema.column_names
 
     @property
     def n_columns(self) -> int:
@@ -426,7 +426,7 @@ def get_column_type(self, column_name: str) -> ColumnType:
         >>> row.get_column_type("a")
         Integer
         """
-        return self._schema.get_type_of_column(column_name)
+        return self._schema.get_column_type(column_name)
 
     # ------------------------------------------------------------------------------------------------------------------
     # Conversion