SnapProcessorRTOS: raise task priority by one

[h3ndrik]

I propose raising the task priority of the SnapProcessorRTOS to 2.
The Main Task is already running at priority level 1 (see: https://docs.espressif.com/projects/esp-idf/en/latest/esp32/api-reference/system/freertos.html#background-tasks)

Feel free to disregard this PR. This might starve the main task and have side-effects. However, I think copying real-time audio data to the peripheral warrants taking priority.

I'm tinkering around with ESPHome and there is too much going on with priority level 1. Raising the priority and setting large buffer sizes makes it almost usable (but not quite).

[pschatzmann]

I suggest to make it a parameter in SnapConfig.h

[h3ndrik]

I force-pushed an update... I'm not sure if you like 1 or 2 as the default...