Implement control of esp32 DAC built-in cosine waveform generator

**Describe the problem you have/What new integration you would like**

The esp32 DAC has a built-in cosine waveform generator, not yet accessible or supported in esphome DAC configuration. This seems simple enough to implement, please. Can this be done via lambda and direct register access? I don't want to create the wave from calculations or lookup tables, for slow waveform output, taking up all chip resources when this is already built in to the chip to work on its own. Please implement control of the DAC's built in cosine generator here: (calling it with at least the parameters of Frequency, On, OFF or start/stop)

output:
- platform: esp32_dac
pin: GPIO25
id: dac_output

reference https://github.com/krzychb/dac-cosine

**Please describe your use case for this integration and alternatives you've tried:**

I'm hoping to use this for on-the-fly signal generation, where I can change at least the frequency to control frequency controlled devices, or for clock generation, all without using program / chip cycle time. Also for inter-device state communication via specific frequency. Audible tone generation for audible state / status would be useful to the blind or for everyone not looking at a screen or LED for status. R2D2 communicates via audible tones. Hey if it's a feature of esp32, I'd like to control it via esphome.

**Additional context**

Start with the ESPHome `esp32_dac` output configuration and compare its available controls with the referenced `dac-cosine` implementation. Define how frequency and on/off or start/stop controls should appear in the configuration, then verify that the built-in cosine generator can be controlled without calculated waveforms or lookup tables.

Written by the indexing model from the issue text.