Merge pull request #7198 from poettering/stdin-stdout

Add StandardInput=data, StandardInput=file:... and more

diff --cc TODO
Simple merge

diff --cc man/systemd.exec.xml
Simple merge

diff --cc src/basic/cgroup-util.c
Simple merge

diff --cc src/basic/fd-util.c
Simple merge

diff --cc src/basic/fd-util.h
Simple merge

diff --cc src/basic/fs-util.c
Simple merge

diff --cc src/basic/hexdecoct.c
Simple merge

diff --cc src/basic/path-util.c
Simple merge

diff --cc src/basic/path-util.h
Simple merge

diff --cc src/basic/proc-cmdline.c
Simple merge

diff --cc src/basic/unit-name.c
Simple merge

diff --cc src/basic/user-util.c
Simple merge

diff --cc src/core/dbus-execute.c
Simple merge

diff --cc src/core/execute.c
Simple merge

diff --cc src/core/execute.h
Simple merge

diff --cc src/core/load-fragment.c
Simple merge

diff --cc src/core/load-fragment.h
Simple merge

diff --cc src/core/main.c
Simple merge

diff --cc src/core/service.c
Simple merge

diff --cc src/core/unit.c
Simple merge

diff --cc src/import/import-common.c
Simple merge

diff --cc src/import/pull-common.c
Simple merge

diff --cc src/machine/machine-dbus.c
Simple merge

diff --cc src/mount/mount-tool.c
Simple merge

diff --cc src/shared/bus-unit-util.c
Simple merge

diff --cc src/systemctl/systemctl.c
Simple merge

diff --cc src/test/test-execute.c
Simple merge

diff --cc src/test/test-fd-util.c
Simple merge

diff --cc test/meson.build
Simple merge