Human readable file size message in validator

[MrTango]

The file validator should return some like this:
The uploaded file is larger than 15.0 MiB!
instead of this:
The uploaded file is larger than 15728640 Bytes!

we could implement a conversion like this:

def sizeof_fmt(num, suffix="B"):
    for unit in ("", "Ki", "Mi", "Gi", "Ti", "Pi", "Ei", "Zi"):
        if abs(num) < 1024.0:
            return f"{num:3.1f} {unit}{suffix}"
        num /= 1024.0
    return f"{num:.1f} Yi{suffix}"

hsize = sizeof_fmt(size)

and use this in the message show to the user.

[davisagli]

Use https://github.com/plone/plone.base/blob/main/src/plone/base/utils.py#L40 rather than writing another one