Add integration scaffolding script

[balloob]

Description:

Inspired by home-assistant/architecture#289

Add a script to scaffold a new integration that includes a manifest, config flow and tests for that config flow. No one should ever be able to complain that it is too difficult to write a new integration. Output of running python3 -m script.scaffold:

Creating a new integration for Home Assistant.

What is the domain?
> paulus

What is the name of your integration?
> Paulus Hub

What is your GitHub handle?
> @balloob

What PyPI package and version do you depend on? Leave blank for none.
> aioballoob==1.0.3

Generating the paulus integration...
Writing homeassistant/components/paulus/error.py
Writing homeassistant/components/paulus/__init__.py
Writing homeassistant/components/paulus/manifest.json
Writing homeassistant/components/paulus/strings.json
Writing homeassistant/components/paulus/const.py
Writing homeassistant/components/paulus/config_flow.py
Writing tests/components/paulus/__init__.py
Writing tests/components/paulus/test_config_flow.py

Running hassfest to pick up new codeowner and config flow.
Warning: mobile_app references integration cloud but it's not a dependency
Warning: proxy references integration camera but it's not a dependency
Warning: auth references integration onboarding but it's not a dependency
Warning: cast references integration cloud but it's not a dependency
Warning: google_assistant references integration camera but it's not a dependency
Warning: onboarding references integration person but it's not a dependency
Warning: owntracks references integration cloud but it's not a dependency
Integrations: 878
Invalid integrations: 0

Running tests
$ py.test tests/components/paulus
Test session starts (platform: darwin, Python 3.7.4, pytest 5.1.1, pytest-sugar 0.9.2)
rootdir: /Users/paulus/dev/hass/home-assistant, inifile: setup.cfg
plugins: sugar-0.9.2, timeout-1.3.3, cov-2.7.1, aiohttp-0.3.0, requests-mock-1.6.0
collecting ...
 tests/components/paulus/test_config_flow.py ✓✓✓                                    100% ██████████

Results (0.20s):
       3 passed

Successfully created the paulus integration!

Checklist:

• The code change is tested and works locally.
• Local tests pass with tox. Your PR cannot be merged unless tests pass
• There is no commented out code in this PR.
• I have followed the development checklist

If the code does not interact with devices:

• Tests have been added to verify that the new code works.

[balloob]

Docs: home-assistant/developers.home-assistant#318