pyramid: Add pyramid charts

[LordBaryhobal]

Pyramid Charts

This pull request adds a new chart type: pyramid charts
This allows the user to show their data in a qualitative diagram

I have tried to make it as flexible as possible to include most use cases

I haven't written any tests for the moment, as I am not familiar with unit tests in Typst. Any help would be appreciated

Features

• Side labels: in addition to inner labels, the user can add labels on the side of the pyramid (west or east)
• Automatic label placement: by default, if an inner label doesn't fit in its level, it is moved outside the pyramid and linked with a small line to improve readability. This behavior can be disabled with the inner-label.force-inside parameter
• Gaps: the user can add gaps in between levels. (If the mode is AREA-HEIGHT, the value is a ratio, and gaps are hence proportional to the topmost level's height)
• Modes:
  • REGULAR (default): Regular pyramid, all levels are the same height, the pyramid is a perfect equilateral triangle
  • WIDTH: All levels are the same height. The topmost level is an equilateral triangle. Each following level's base width is then proportional to its value (higher value => larger base)
  • HEIGHT: The pyramid is a perfect equilateral triangle, but each level's height is proportional to its value
  • AREA-HEIGHT: The pyramid is a perfect equilateral triangle, but each level's area is proportional to its value (only the height is adapted)

Examples

Mode: REGULAR

Mode: WIDTH

Mode: HEIGHT

Mode: AREA-HEIGHT

[johannes-wolf]

Thank you, looks great! We can add tests in a follow-up PR.

[johannes-wolf]

I've opened a PR with some simple tests here: #90