New article: lean production

# Title: [Article] lean production

- [ ] What is this about: “What is this practice about”? Which existing (or new) problems does this practice solve?
One of the production methods focused on the definition of specific value by specific products.

- [ ] Read more here: The starting point for your research (You can use different sources if you have better ones)
https://en.wikipedia.org/wiki/Lean_manufacturing

- [ ] Pick the corresponding labels:
- Stage:research
- Stage:building_team
- Stage:development
- Stage:launch
- Stage:maintenance
- Stage:phase_out

## How to contribute:
- Follow our [Contribution guide](https://github.com/DXHeroes/knowledge-base-content/blob/master/CONTRIBUTING.md)
- How to [Git and Pull Requests]( https://github.com/firstcontributions/first-contributions/blob/master/README.md)
- How to [Markdown](https://guides.github.com/features/mastering-markdown/), [Markdown interactive demo](https://www.markdowntutorial.com/lesson/1/) or [Google Docs Addon](https://gsuite.google.com/marketplace/app/docs_to_markdown/700168918607)

Read CONTRIBUTING.md first, then use the linked Wikipedia article as the starting point for research. Create the lean production article in the repository's established content format, explaining what the practice is and which problems it addresses; done means the article is complete and follows the contribution guidance.

Written by the indexing model from the issue text.