Create a barebones Image package module

[jabraham17]

Adds a new unstable Image package module for writing images from Chapel arrays.

Available symbols

• enum imageType: the type of image a given function is working with
• writeImage(image, format, pixels): writes a pixels array in the given format (currently only BMP) to image
• downSample(arr): takes an array and converts it to an array of pixels
• interpolateColor(arr, colorA, colorB): takes an array and converts it to an array of pixels, by interpolating between two rgb colors
• scale(arr, factor): takes an array and scales it by a factor
• mediaPipe: utilizes ffmpeg to allow writing rgb pixels to a mp4

[Reviewed by @DanilaFe]