`bevy_gizmos`: Monospace stroke font for text gizmos

## What problem does this solve or what need does it fill?

Currently text gizmos use a proportional font. I had planned to use a monospaced font but I wasn't able to find a suitable stroke font that was simple, attractive and readable.

## What solution would you like?

Three options:

1. Create a new stroke font for `bevy_gizmos`.
2. Adjust the existing stroke font (it's public domain and free to modify).
3. Find a suitable permissively licensed stroke font we can use.

There isn't a standard format for stroke fonts. At the moment we just store a list of points, where strokes are ranges into the list of points, and glyphs are ranges into the list of strokes.