fix: missing app icon for AppImage on Linux

[kittaakos]

Motivation

Manually set the application icon for the AppImage on Linux.

Change description

The app icon is available from the AppImage on Linux.

Other information

Closes #131

Reviewer checklist

• PR addresses a single concern.
• The PR has no duplicates (please search among the Pull Requests before creating one)
• PR title and description are properly filled.
• Docs have been added / updated (for bug fixes / features)

[per1234]

As can be seen in the screenshot shared in the PR message, the clear source icon is seriously degraded through the scaling down from the original 512x512 image

to 64x64:

It is even worse at my custom Settings > Appearance > Dock > Icon size setting of 16:

However, a visually low quality icon is a very significant improvement over no icon (as reported in #131 (comment) and which I experience on my Ubuntu 20.04 machine) or a generic fallback gear icon as I experience on my Ubuntu 22.04 machine. So I recommend this PR be merged as is rather than delay this important advancement in the pursuit of perfection. I am happy to create a follow up issue to track the task of finding a way to improve the quality of the displayed icon.

[kittaakos]

he clear source icon is seriously degraded

I also noticed it 😕 I wanted to compare the UX with Theia Blueprint, but the icon is missing with the latest version: eclipse-theia/theia-ide#296.

a visually low quality icon is a very significant improvement over no icon

I agree.

I am happy to create a follow up issue to track the task of finding a way to improve the quality of the displayed icon.

Thank you!

[per1234]

I have now submitted the follow-up issue to track the problem of the low visual quality of the icon: #2194

I wanted to compare the UX with Theia Blueprint

I got lucky and initially opened up an older version of Blueprint that I happened to have installed on my Linux machine so I was able to see the icon. It is also degraded, but the nature of the source image makes the degradation a bit less noticeable than it is on Arduino IDE's icon:

I was going to mention that in my review, but then I got confused when I downloaded the latest Blueprint and found it didn't have any icon at all (eclipse-theia/theia-ide#296).