Make the AppImage

[ooshlablu]

What does this PR do?

Build and publish the AppImage for Composer

Motivation

Trying to get to build parity with the Performous repo.

[github-actions[bot]]

Download the artifacts for this pull request:

• Composer-2.0rc1-49-342915d-alpha.AppImage.zip
• Composer-2.0rc1-49-342915d-alpha-debian_10.deb.zip
• Composer-2.0rc1-49-342915d-alpha-debian_11.deb.zip
• Composer-2.0rc1-49-342915d-alpha-fedora_34.rpm.zip
• Composer-2.0rc1-49-342915d-alpha-fedora_35.rpm.zip
• Composer-2.0rc1-49-342915d-alpha-ubuntu_20.04.deb.zip
• Composer-2.0rc1-49-342915d-alpha-ubuntu_22.04.deb.zip

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