Icon update for ptcollab!

[germe-deb]

As discussed in discord, this is a huge change and it's thougt to be updated in a major version, (like saying "hey I'm back with new things")

This icon tries to follow this guide (and specifically tackling this point), but it follows the overall ptcollab design, while adding a bit more of context to the icon, not just being a "player.svg".

This is the new icon:

I made it this way because:

• I wanted to simbolize the cooperation feature of the program, adding multiple notes (and multiple colors)
• I wanted to make it more appealing to see, this will probably attract new users, who knows
• wanted to look better, compared to the original pxtone collage icon that follows a pixel art style

also, just for curiosity here you have my design process. just because I think it's cool to look at it.

As this project is community driven, this will keeps as a draft pull request until there is some community approval