Increase default CIRCUITPY_PYSTACK_SIZE to at least 2048

[dhalbert]

CIRCUITPY_PYSTACK_SIZE is currently 1536 for all boards except one specialized board. We have seen "pystack exhausted errors on PyPortal projects with this size, such as https://forums.adafruit.com/viewtopic.php?t=217498. I was able to get that NASA image project working by increasing PYSTACK to 2048. Other threads in the forums have increased it to 4k or greater, though they may have not tried to determine the minimum size.

Currently CIRCUITPY_PYSTACK_SIZE can be set in settings.toml, but it's something of a support burden help people with that.

How about increasing the default to at least 2048, except maybe on SAMD21? I think that would cover Portal projects that might be suffering otherwise.

I would plan to do this for 9.2.x

[tannewt]

I'd rather change this in 10.x since it will reduce the heap size. (Plus I want us to focus on 10.x)

[dhalbert]

In that case I will add instructions to various PyPortal projects to increase the pystack.