[macOS] Add support for app shortcuts

[flavioislima]

Implements #723

Adds shortcut inside HOME/Applications folder
The shortcut is a TITLE.app that contains a shell script to call Heroic with the -no-gui option.
It also contains and icon for the game and a generic plist file that is needed for the app to run.
Used nativeImage from electron to resize the image and https://www.npmjs.com/package/@shockpkg/icon-encoder to convert it to .icns.

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Use the following Checklist if you have changed something on the Backend or Frontend:

• Tested the feature and it's working on a current and clean install.
• Tested the main App features and they are still working on a current and clean install. (Login, Install, Play, Uninstall, Move games, etc.)
• Created / Updated Tests (If necessary)
• Created / Updated documentation (If necessary)

[arielj]

Looks good and the shortcut has the right icon and shows up in the apps launcher properly, that's great.

I'm having an issue when I try to run a game using the shortcut, but I don't know if it's because I try running the app with yarn

Unable to find Electron app at /heroic:/launch/1207659026

Cannot find module '/heroic:/launch/1207659026'
Require stack:
- /Users/arielj/dev/oss/HeroicGamesLauncher/node_modules/electron/dist/Electron.app/Contents/Resources/default_app.asar/main.js

the content of the run.sh is:

/Users/arielj/dev/oss/HeroicGamesLauncher/node_modules/electron/dist/Electron.app/Contents/MacOS/Electron --no-gui heroic://launch/1207659026

if it helps

(I'm going to try installing the binary from this PR in a moment)

[arielj]

Using the installed app works fine, looks like it doesn't like the path when running as dev, but not a big deal