Add Rosou SS4 Ventilator (leshow.fan.ss4) support (Closes: #112)

[syssi]

Requires python-miio 0.5.5.

Supported methods:

• set_power [power] on/off
• set_mode [mode] Manual/Sleep/Strong/Natural
• set_speed 0...100
• set_oscillate true/false
• set_buzzer true/false
• delay_off [minutes]

Supported properties:

• power
• mode
• speed
• buzzer
• oscillate
• delay_off_countdown
• error_detected

[github-actions]

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