Add the ability to generate a dmg for mac distribution

[Robert Leach]

USE CASE: WHAT DO YOU WANT TO DO?

Make the app installation a polished & professional experience by following established conventions for mac installations

STEPS TO REPRODUCE AN ISSUE (OR TRIGGER A NEW FEATURE)

1. Download a .dmg file
2. Mount the disk image by double-clicking
3. Allow installation by developer not registered with Apple
4. Drag TreeView3.app to an Applications directory alias

CURRENT BEHAVIOR

Currently, users are downloading a zipped jar file.

EXPECTED BEHAVIOR

Installation via dmg download, mount, & drag

DEVELOPERS ONLY SECTION

SUGGESTED CHANGE (Pseudocode optional)

Add dmg code to the gradle build file & set up a bitbucket pipeline to produce the dmg automatically.

FILES AFFECTED (where the changes will be implemented) - developers only

build.gradle

LEVEL OF EFFORT - developers only

medium

COMMENTS

Currently branched off of branch issue482.

[Robert Leach]

Duplicate of #482.

[Robert Leach]

Issue #482 resulted in the command gradle createDmg to generate a dmg.