moansubs plugin index

This branch serves the Stash package index for the moansubs plugin. It is published by the release workflow; there is nothing to browse here by hand.

Add the URL matching the architecture Stash itself runs on, under Settings → Plugins → Add source. The exec half is a native binary, so an arm64 NAS needs the arm64 index even when the server runs elsewhere.

• https://plugins.moansubs.org/plugin/amd64/index.yml
• https://plugins.moansubs.org/plugin/arm64/index.yml

Each index points at bundles attached to a release, so adding it once reaches every later release. See plugin/README.md.