feat(esphome): Add initial irrigation system configuration

This commit introduces the initial ESPHome configuration for the irrigation system.

- `irrigation_system.yaml`: ESPHome configuration with Modbus valve control.

- `create_secrets.py`: Script to generate `secrets.yaml`.

- `secrets.yaml.example`: Example secrets file.

- `requirements.txt`: Python dependencies.

- `.gitignore`: Standard ESPHome gitignore file.
Signed-off-by: Eduard Iten <eduard@iten.pro>

software/esphome/secrets.yaml.example

@@ -0,0 +1,4 @@
+wifi_ssid: 'PUT YOUR WIFI SSID HERE'
+wifi_password: 'PUT YOUR WIFI PASSWORD HERE'
+api_key: 'PUT YOUR KEY HERE OR USE create_secrets.py'
+ota_password: 'PUT YOUR KEY HERE OR USE create_secrets.py'