feat(appdata): Improve appdata for AppStream 1.0

[ghost]

feat(appdata): Improve appdata for AppStream 1.0

• Add the <developer><name> tag
• Mark the <developer_name> tag as deprecated
• Improve appstreamcli arguments

chore: remove categories

"Icons and categories

If there’s a type="desktop-id" launchable, they get pulled from it. Most of the icon not found errors with the flathub builder can be traced down to the launchable value not matching the desktop file name.

Don’t set them in the AppData unless you want to override them (even though then it might be a better idea to patch the desktop file itself)."

[ghost]

The commit title changed.

[FineFindus]

Thanks!