Remove icons for apps which don't want them

[clefebvre]

Some apps specifically asked not to be themed:

https://stopthemingmy.app

As much as possible this should be respected and icons for these apps should be removed from our themes.

From the website above I made the following list to keep track of this:

• authenticator
• aviator
• blanket
• blurble
• bottles
• citations
• contrast
• decoder
• dialect
• feedreader
• fractal
• fragments
• fretboard
• geary
• generator
• gradience
• gradio
• graphs
• Highscore
• icon library
• icon preview
• khronos
• lollypop
• lorem
• newsflash
• obfuscate
• organizer
• password-safe
• pika backup
• pitivi
• podcasts
• random
• remotely
• secrets
• share preview
• shortwave
• teleport
• timetrack
• uberwriter
• webfont kit

[clefebvre]

Only 3 apps had icons in Mint-X, they'll be removed.