Add projects: `crystaltoolkit` and `elementari`

[janosh]

Project details:

• Github URLs:
  • https://github.com/materialsproject/crystaltoolkit
  • https://github.com/janosh/elementari
• Category: Visualization
• Labels: Python (CTK), JS (elementari)
• License: MIT
• Package Managers: pip install crystal-toolkit && npm install elementari

Additional context:

disclaimer: i contribute to both

[Irratzo]

Hi @janosh , thank you for the suggestions. I'll add them momentarily like this.

- name: Crystal Toolkit
  github_id: materialsproject/crystaltoolkit
  category: visualization
  # labels: none
  license: MIT
  pypi_id: crystal-toolkit
- name: Elementari
  github_id: janosh/elementari
  category: visualization
  labels: ["lang-js"]
  license: MIT
  npm_id: elementari

Remarks.

• Why no "lang-py" label for CTK? "lang-py" is the implicit default of the list. Only if it is NOT Python, the language label is added. This is the current list convention.