feat: nutrient bottle level tracker with progress bars and Telegram alerts

[m0nk1111]

Summary

Tracks remaining liquid levels in nutrient bottles by monitoring how much each dosing pump has dispensed. Provides visual progress bars in the Mycodo dashboard and sends Telegram alerts when bottles need refilling.

Features

• 1-8 configurable bottle/pump slots: Each with Mycodo output selection, bottle capacity (ml), and ml/min calibration
• Visual progress bars: Color-coded (green >25%, yellow >10%, red ≤10%) in Function Status widget
• Telegram alerts: Configurable threshold (default 15%) with repeat suppression (default 6h)
• Reset commands: "Reset All Bottles" + individual per-bottle reset buttons
• Persistent state: Bottle placement timestamps and usage survive restarts
• Dashboard widget: function_status_always() works even when function is deactivated
• InfluxDB logging: Remaining ml per bottle written as measurement channels

Dashboard Widget Preview

The function status shows colored bars per bottle:

Pump A (Nutrient A): ████████████████░░░░ 82.3% (823 / 1000 ml)
Pump B (Nutrient B): ████████░░░░░░░░░░░░ 41.5% (415 / 1000 ml)
Pump C (pH Down):    ████░░░░░░░░░░░░░░░░ 18.2% (91 / 500 ml)  ⚠️

Testing

Tested in production on RPi 4B + Mycodo v8.16.2 tracking 8 dosing pumps over 4+ weeks.

Checklist

• No hardcoded UUIDs or installation-specific values
• All strings in English
• GPL-3.0 license header
• Uses lazy_gettext for translatable labels
• Valid Python syntax
• Follows Mycodo custom function conventions
• Unit tests (to be added before upstream PR)