[Unittest] introduce `FactoryBoy` for unittest and make a file or a directory for factories

[siruku6]

official reference of FactoryBoy

https://factoryboy.readthedocs.io/en/stable/index.html https://faker.readthedocs.io/en/master/providers.html

other references

• other github sample
  https://github.com/thinkAmi-sandbox/Django_factory_boy_sample/blob/master/myapp/tests/factories.py
• Django + factory_boyで、1対多や多対多のリレーションを持つテストデータを作る
  https://thinkami.hatenablog.com/entry/2016/04/22/233958