Package for Flatpak

[Grafcube]

Closes #737

This patch adds flatpak support. I built and installed it on my branch with these commands:

pnpm build
pnpm electron-builder --linux flatpak
flatpak install --bundle 'pack/YouTube Music-3.3.6-x86_64.flatpak'

A few things to note, I need to write a separate yml to publish to flathub which repeats a lot of metadata (electron builder doesn't currently have any way to publish to flathub automatically). According to the flatpak app submission guidelines:

Flathub is primarily intended as a service that is used by app developers to distribute their apps. Our goal is to give developers control of their apps and to allow them a closer relationship with their users without middlemen getting in the way. However, as part of setting up Flathub, some applications are being distributed on Flathub without the involvement of their developers. We would prefer that these applications are controlled by their authors.

I am perfectly fine with maintaining the flatpak myself.

The appstream metadata should probably contain content warnings since YT music also has explicit content. I've left it blank for now. It also needs to be packaged manually since electron builder doesn't yet support adding it (see electron-userland/electron-builder#1993). I'll manually include it in the manifest until that issue is resolved. The appstream file is useful for all linux packages, not just flatpak, which is why I've included it in the PR.

If you don't want to wait, you can checkout my branch and install it yourself with the above commands. Cheers!

[razzeee]

You can try using https://hughsie.github.io/oars/generate.html to generate the missing oars data

[Grafcube]

You can try using https://hughsie.github.io/oars/generate.html to generate the missing oars data

Here's what I got. I'm unsure if it's accurate since it's only audio and not video.

  <content_rating type="oars-1.1">
    <content_attribute id="drugs-alcohol">mild</content_attribute>
    <content_attribute id="drugs-narcotics">mild</content_attribute>
    <content_attribute id="drugs-tobacco">mild</content_attribute>
    <content_attribute id="sex-nudity">mild</content_attribute>
    <content_attribute id="sex-themes">mild</content_attribute>
    <content_attribute id="language-profanity">moderate</content_attribute>
    <content_attribute id="social-info">intense</content_attribute>
    <content_attribute id="money-purchasing">intense</content_attribute>
    <content_attribute id="money-advertising">intense</content_attribute>
  </content_rating>

[ArjixWasTaken]

is there any point in setting oars ratings to anything other than intense?
we do not have control over youtube's content, so we cannot explicitly set age ratings

[razzeee]

Won't this also play video in some cases?

[MulverineX]

Also social-info shouldn't be marked intense, anonymous users can use this app

[Grafcube]

Also social-info shouldn't be marked intense, anonymous users can use this app

I'm pretty sure the algorithm still works for anonymous users.

From https://hughsie.github.io/oars/generate.html
If the user is able to "enable" NSFW or "adult" content, then this should be included in the assessment even if it is turned off by default.

This makes me think that it should be the "worst case" for all the fields.