add device<->host transfer mappers #1629

Job	Run time
Documentation	1m 52s
Mypy	1m 57s
Tests for downstream project meshmode	12m 4s
Tests for downstream project grudge	10m 11s
Pylint	1m 54s
Pytest Conda Py3 Intel	2m 29s
Tests for downstream project mirgecom	6s
Examples Conda Py3	1m 34s
Tests for downstream project mirgecom_examples	4s
Pytest Conda Py3 POCL	2m 33s
Typos	4s
Ruff	5s
	34m 53s

Provide feedback