OV7670 Support

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

The OV7670 is a really cheap camera and it would be great to have it supported. #835 opened an issue but unfortunately it is now locked.

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

I'm not able to use the camera with ESPHome. The alternative is to use https://github.com/bitluni/ESP32CameraI2S (more info there: https://bitluni.net/esp32-i2s-camera-ov7670)

I tried this without success:

```yml
# OV7670
esp32_camera:
name: My Camera
external_clock:
pin: GPIO32
frequency: 20MHz
i2c_pins:
sda: GPIO21
scl: GPIO22
data_pins: [GPIO4, GPIO12, GPIO13, GPIO14, GPIO15, GPIO16, GPIO17, GPIO27]
vsync_pin: GPIO34
href_pin: GPIO35
pixel_clock_pin: GPIO33
resolution: 640x480
jpeg_quality: 10
max_framerate: 6 fps
idle_framerate: 0.1 fps
```

I have this in the logs:

```
[22:57:02][E][esp32_camera:123]: Setup Failed: ESP_ERR_NOT_SUPPORTED
[22:57:02][E][component:082]: Component esp32_camera is marked FAILED
```

I tried with `esp-idf` and `arduino` framework.

**Additional context**

Start at the esp32_camera component and reproduce the reported ESP_ERR_NOT_SUPPORTED result with the OV7670 YAML configuration in this issue, using both listed frameworks if needed. Determine the integration requirements for this camera; done means the configuration initializes successfully and the camera produces usable frames without the reported failure.

Written by the indexing model from the issue text.