JHDBot Dockerfile Rebuild

[gwagstaff]

• Update JHDBot dockerfile to not use root permissions, multi-stage build (reduce final image size), move /gifs inside container instead of volume mounted, add basic discordpyhealthcheck
• Update requirements.txt with specific packages + versions
• Update docker-compose.yml to remove un-used web-app2 & setup frontend & backend networks for proper isolation
• Upgrade github actions to updated workflows, add SHA tags (to allow rollbacks if needed), and build AMD + ARM images