refactor: Default config args

There is an upcomming concept that will take a simplified approach to
default project config. Refactoring these switches in advance

src/cally/cli/__init__.py

@@ -31,14 +31,7 @@ def get_commands(package_name: str) -> List:
 
 @click.group()
 @click.option(
-    '--core-config',
-    type=click.Path(path_type=Path),
-    default=Path(Path.home(), '.config', 'cally.yaml'),
-    envvar='CALLY_CORE_CONFIG',
-    help='Path to the core config file',
-)
-@click.option(
-    '--project-config',
+    '--config',
     type=click.Path(path_type=Path),
     default=Path(Path.cwd(), '.cally.yaml'),
     envvar='CALLY_PROJECT_CONFIG',
@@ -48,8 +41,7 @@ def get_commands(package_name: str) -> List:
 @click.pass_context
 def cally(
     ctx: click.Context,  # noqa: ARG001
-    core_config: click.Path,  # noqa: ARG001
-    project_config: click.Path,  # noqa: ARG001
+    config: click.Path,  # noqa: ARG001
 ) -> None:
     """
     Top level click command group for Cally