Organize functions into modules

[aazuspan]

This would be a lot more usable if functions were organized into modules that could be accessed through a top-level import. Below is a draft structure. Functions in italics haven't been implemented yet.

• terrain
  • HLI
  • TPI
  • rumpleIndex
• fire
  • burnSeverity
  • fireProgression
• climate
  • relativeHumidity
  • vaporPressureDeficit
  • windVelocity(u, v)
  • hotDryWindyIndex
• ui
  • categoricalLegend
  • continuousLegend
• misc/utils/spectral/? (not sure what to name this module)
  • darkObjectSubtraction
  • matchHistogram (see ee_extra implementation)
  • normalizeImage
  • otsuThreshold

Pseudocode:

var tools = require("users/aazuspan/geeTools:tools");

tools.fire.burnSeverity( ... )
tools.ui.categoricalLegend( ... )

[aazuspan]

See https://aazuspan.github.io/optimizing-module-structure-in-earth-engine.html for performance considerations.