Fix beszel server stats cpu load metrics

[Nedra1998]

Beszel changed some of their APIs, so this updates to account for that. It also makes a few additional changes:

• Updates to use the new Beszel API schema for the CPU Load metrics
• Supports Email + Password authentication in addition to tokens from: Add e-mail + password authentication to beszel-server-stats widget #239
• RAM and DISK popover now show the percentage for each row.
• DISK uses the maximum disk percentage (not always root)
• Removed the system info popover (Beszel changed that to a separate API which otherwise isn't needed for the widget).