Switch to Mediux API

[Buried-In-Code]

• Switch scraping for using the Mediux GraphQL API, Closes #35
• Switch from PlexAPI lib to using plex json URL
• Fix CodeQL security
• Merge Show, Collection and Movie commands into Media command
• Refine Plex and Jellyfin services (Need to check for regressions)
• Simple test suite
• Add warning for large image files, Closes #44
• Select preferred set when priority user has multiple, Closes #40
• Support for Python 3.14
• Use updated authentication headers for Jellyfin, Closes #60