ACIM exporter should use a consistent tag for execution status

[Petingo]

Currently, the ACIM exporter uses "executed" for timber's status but "status" for cuts and holes (the Done/NotDone status). I suggest modifying the tag for timber from "executed" to "status" to keep them consistent as they represent a similar concept.

Reference:

augmented-carpentry/py/pypi/ACPy/ac_acim.py

Line 42 in 1d2ad67

timber_executed_et = ET.SubElement(timber_et, "executed")