feat: make API optional

Add include_api to the cookiecutter context. If set to NO then the api module won't be included. This is mostly useful for tiny "pure Django" apps with the traditional request -> render webapp model.

Tweak the logic surrounding adding Django social auth. In general we assume that apps with UI disabled but API enabled are "pure API" applications and don't need social auth. Any other combination results in social auth being added.

Tested by bootstrapping a new Django project for the Regent House Ballot voting site.

hooks/post_gen_project.py

@@ -7,9 +7,14 @@ import os
 REMOVE_PATHS = [
 {%- if cookiecutter.include_ui == 'NO' %}
     "{{ cookiecutter.ui_module }}",
+{% endif %}
+{%- if cookiecutter.include_ui == 'NO' and cookiecutter.include_api == 'YES' %}
     "{{ cookiecutter.project_module }}/pipelines.py",
     "{{ cookiecutter.project_module }}/test/test_pipelines.py",
 {% endif %}
+{%- if cookiecutter.include_api == 'NO' %}
+    "{{ cookiecutter.api_module }}",
+{% endif %}
 ]
 
 print("Removing any paths not needed in boilerplate...")