Add a function to set the volume of the rtttl buzzer

**Describe the problem you have/What new integration you would like**
Add possibility to set the volume of the buzzer. ( https://esphome.io/components/rtttl.html )

**Please describe your use case for this integration and alternatives you've tried:**
Use the M5STICK CPlus as a temperature alarm. The default sound volume of the buzzer is too low.

**Additional context**

It is possible in this project: https://github.com/StarsoftAnalysis/ESP8266RTTTLPlus

Start with the RTTTL component documentation at https://esphome.io/components/rtttl.html and compare the volume-related behavior in the linked ESP8266RTTTLPlus project. Done means the buzzer volume can be set for the requested temperature-alarm use case and the existing RTTTL behavior remains usable.

Written by the indexing model from the issue text.