.. the primary user of which will be the camera, since the framebuffers
must be allocated via esp-idf allocation function and never from the
gc heap.
A board can have a default value, and the value can also be set in the
/.env file using the key CIRCUITPY_RESERVED_PSRAM with the value being
the reserved size in bytes.
Co-authored-by: Dan Halbert <halbert@adafruit.com>
os.getenv() will use it (when available) to load variables from
/.env
This will also be useful when we need secrets or config for
CircuitPython outside of the VM (like WiFi credentials.)
Fixes#4212
