Supports multiple rclone remotes and dynamic mounts

[totza2010]

Refactors logic to enable handling multiple rclone remotes, mountpoints, and ports using arrays and dynamic environment variable parsing.

Improves mount, serve, healthcheck, and refresh workflows to work with multiple remotes, enabling parallel operations and per-remote scheduling.

Cleans up legacy single-remote logic and simplifies configuration, making extension and maintenance easier.