Transformations and PyPi Deployment

What's Changed

• Fix extinction wavelength limits by @aswinpvijayan in #829
• Switching to a Box server and using a yaml file for file locations by @WillJRoper in #830
• Moving dense_basis install to an optional dependency by @WillJRoper in #831
• Adding a "weighting variable" to a Grid by @WillJRoper in #812
• Simplifies the unit system by introducing "unit categories" by @WillJRoper in #826
• Attenuation operation generalised to Transformation (+ butterfly effect) by @WillJRoper in #827
• Adding a deployment workflow by @WillJRoper in #833

Full Changelog: v0.7.0-beta...v0.8.0-beta