Add option to display an artwork in the background of the media playe…

[gillesbergerp]

Description

Allow for adding a background image for the media player

Types of changes

• 🐛 Bug fix (non-breaking change which fixes an issue)
• 🚀 New feature (non-breaking change which adds functionality)
• 🌎 Translation (addition or update a translation)
• ⚠️ Breaking change (fix or feature that would cause existing functionality to change)

Checklist

• My code follows the code style of this project.
• My change requires a change to the documentation.
• I have updated the documentation accordingly.
• I have tested the change locally.
• I followed the steps if I add a new language .

[piitaya]

Hello 🙂 Thank for your contribution. Please open discussions before adding some options. I want to keep Mushroom simple and I do not prefer to add ton of options so not all PR will be accepted.

[RickeyWard]

@gillesbergerp I love this feature!

I have no authority here, but I do have some suggestions when contributing to open source that might help with getting your PRs merged in the future.

1. Git history is important! Try not to change formatting across lines of code you don't need to change. It looks like you might have used some kind of auto formatter which changed whitespace across all the files you touched. This makes it look like those lines have been changed recently when they really haven't. It makes bug hunting and change tracking more difficult to manage. Not only that, it makes your PR harder to review as its harder to tell what new code was actually added.

2. When there's a PR template, try not to remove anything other than comments <!-- comments usually look like this -->. Some repos have very strict rules and won't accept any changes, while typically it just makes it look like you're not willing to play by the rules. (some repos don't care at all, but I've rarely seen those)