Update to eclipse-temurin:21 and remove appuser #1120

Job	Run time
cpp-lib-build (macos-12, clang, ON)	3m 18s
cpp-lib-build (macos-12, clang, OFF)	4m 52s
build (macos-12, tool)	1m 27s
cpp-lib-build (macos-12, gcc, ON)	1m 8s
build (macos-12, cpp)	17m 48s
cpp-lib-build (macos-12, gcc, OFF)	3m 58s
build (macos-12, csharp)	7m 34s
cpp-lib-build (ubuntu-20.04, clang, ON)	2m 53s
build (macos-12, dart)	4m 43s
cpp-lib-build (ubuntu-20.04, clang, OFF)	4m 12s
build (macos-12, go)	4m 14s
cpp-lib-build (ubuntu-20.04, gcc, ON)	2m 49s
build (macos-12, java)	4m 50s
cpp-lib-build (ubuntu-20.04, gcc, OFF)	4m 9s
build (macos-12, javascript)	2m 3s
cpp-lib-build (windows-2022, clang, ON)	3m 14s
build (macos-12, typescript)	13m 16s
cpp-lib-build (windows-2022, clang, OFF)	4m 57s
build (macos-12, php)	2m 58s
build (macos-12, python3)	1m 49s
cpp-lib-build (windows-2022, cl)	4m 33s
build (ubuntu-20.04, tool)	1m 16s
build (ubuntu-20.04, cpp)	17m 39s
build (ubuntu-20.04, csharp)	5m 45s
build (ubuntu-20.04, dart)	4m 0s
build (ubuntu-20.04, go)	2m 38s
build (ubuntu-20.04, java)	3m 26s
build (ubuntu-20.04, javascript)	1m 56s
build (ubuntu-20.04, typescript)	9m 55s
build (ubuntu-20.04, php)	1m 32s
build (ubuntu-20.04, python3)	1m 21s
build (windows-2022, tool)	1m 53s
build (windows-2022, cpp)	23m 40s
build (windows-2022, csharp)	6m 29s
build (windows-2022, dart)	4m 56s
build (windows-2022, go)	6m 7s
build (windows-2022, java)	2m 11s
build (windows-2022, javascript)	4m 23s
build (windows-2022, typescript)	20m 23s
build (windows-2022, php)	2m 30s
build (windows-2022, python3)	1m 46s
	3h 44m 31s

Provide feedback