Remove libraries folder from scaffolded workspace (#29158)

Summary:
As title.


## How I Tested These Changes
BK

Author: gibsondan

examples/docs_snippets/docs_snippets/guides/dg/workspace/2-tree.txt

@@ -2,7 +2,6 @@ cd dagster-workspace && tree
 
 .
 ├── dg.toml
-├── libraries
 └── projects
     └── project-1
         ├── pyproject.toml

python_modules/libraries/dagster-dg/dagster_dg/cli/init.py

@@ -95,8 +95,6 @@ def init_command(
     ├── <workspace_name>
     │   ├── projects
     |   |   └── <Dagster projects go here>
-    |   ├── libraries
-    |   |   └── <Shared packages go here>
     │   └── pyproject.toml
 
     """

python_modules/libraries/dagster-dg/dagster_dg/cli/scaffold.py

@@ -179,8 +179,6 @@ def scaffold_workspace_command(
     ├── <workspace_name>
     │   ├── projects
     |   |   └── <Dagster projects go here>
-    |   ├── libraries
-    |   |   └── <Shared packages go here>
     │   └── pyproject.toml
 
     """

python_modules/libraries/dagster-dg/dagster_dg/templates/WORKSPACE_NAME_PLACEHOLDER/libraries/.gitkeep

@@ -99,7 +99,7 @@ def test_init_success_workspace(
         assert Path("dagster-workspace").exists()
         assert Path("dagster-workspace/dg.toml").exists()
         assert Path("dagster-workspace/projects").exists()
-        assert Path("dagster-workspace/libraries").exists()
+        assert not Path("dagster-workspace/libraries").exists()
         assert Path("dagster-workspace/projects/helloworld").exists()
         assert Path("dagster-workspace/projects/helloworld/src/helloworld").exists()
         assert Path("dagster-workspace/projects/helloworld/pyproject.toml").exists()

python_modules/libraries/dagster-dg/dagster_dg_tests/cli_tests/test_init_command.py

@@ -47,7 +47,7 @@ def test_scaffold_workspace_command_success(monkeypatch) -> None:
         assert Path("dagster-workspace").exists()
         assert Path("dagster-workspace/dg.toml").exists()
         assert Path("dagster-workspace/projects").exists()
-        assert Path("dagster-workspace/libraries").exists()
+        assert not Path("dagster-workspace/libraries").exists()
 
         result = runner.invoke("scaffold", "workspace")
         assert_runner_result(result, exit_0=False)
@@ -61,7 +61,7 @@ def test_scaffold_workspace_command_name_override_success(monkeypatch) -> None:
         assert Path("my-workspace").exists()
         assert Path("my-workspace/dg.toml").exists()
         assert Path("my-workspace/projects").exists()
-        assert Path("my-workspace/libraries").exists()
+        assert not Path("my-workspace/libraries").exists()
 
         result = runner.invoke("scaffold", "workspace", "my-workspace")
         assert_runner_result(result, exit_0=False)

python_modules/libraries/dagster-dg/dagster_dg_tests/cli_tests/test_scaffold_commands.py

@@ -39,7 +39,7 @@ def test_context_in_workspace(config_file: ConfigFileType):
         isolated_example_workspace(runner, workspace_config_file_type=config_file),
     ):
         # go into a subdirectory to make sure root resolution works
-        path_arg = Path.cwd() / "libraries"
+        path_arg = Path.cwd() / "projects"
 
         context = DgContext.for_workspace_environment(path_arg, {})
         assert context.root_path == Path.cwd()