StartCamera's default FRAMESIZE_SVGA causes stack overflow during capture after set_framesize with bigger resolution is used

[MichaelXt]

Tracking the issue with timeouts / stack overflow due to buffer sizes issue in esp32 camera driver.
The issue manifests as no image received on Get still button call in case if high resolution and high quality is choose in the UI, with the scene capture in good lighting conditions with lots of details.

The underlying issue is in esp camera driver:
espressif/esp32-camera#514

esp32-cam-webserver could either:

1. wait for a fix (if it will be fixed) in the esp camera
2. use config.frame_size = FRAMESIZE_UXGA; in StartCamera
3. call esp_camera_deinit + esp_camera_init on frame size change set_framesize

For most users of the esp32-cam-webserver # 2 workaround is the easiest to implement.