Agvis

* Replaced simple.http server backend with Flask
- Uses Gunicorn as the WSGI
- Defaults to flask development server on non-unix environments

* Major Improvements to the IDR:
- Added the ability to upload more than one file at a time
- Added the ability to read CSV files
- Updated the file parsing to now handle ANDES output files as a format

* Unit testing

* Added github actions

* Increased map zoom

* Dynamic Legend

* Extensive developer documentation

* Various QoL improvements

What's Changed
* Legend bar by zmalkmus in https://github.com/CURENT/agvis/pull/53
* Compress images by zmalkmus in https://github.com/CURENT/agvis/pull/65
* AGVis Update 4.0 by zmalkmus in https://github.com/CURENT/agvis/pull/72


**Full Changelog**: https://github.com/CURENT/agvis/compare/v3.2.1...v4.0.0

The Independent Data Reader

- Added in the ability to interpret simulation data and animate it:
- Playback Bar for playing the animation at different speeds
- Frequency, Voltage Magnitude, and Voltage Angle displays
- Customizable ranges for those displays
- Customizable Timestamps
- More than one simulation playing at once