execute: Add new PassEnvironment= directive This directive allows passing environment variables from the system manager to spawned services. Variables in the system manager can be set inside a container by passing `--set-env=...` options to systemd-spawn. Tested with an on-disk test.service unit. Tested using multiple variable names on a single line, with an empty setting to clear the current list of variables, with non-existing variables. Tested using `systemd-run -p PassEnvironment=VARNAME` to confirm it works with transient units. Confirmed that `systemctl show` will display the PassEnvironment settings. Checked that man pages are generated correctly. No regressions in `make check`.

shell-completion: systemd-run: add the property RuntimeDirectory

shell-completion: systemd-run: add the property ProtectHome

shell-completion: systemd-run: add the property ProtectSystem

shell-completion: systemd-run: add new property EnvironmentFile

shell-completion: systemd-run: add new properties "ReadWriteDirectories", "ReadOnlyDirectories", "InaccessibleDirectories"

shell-completion: systemd-run: add property OOMScoreAdjust

shell-completion: systemd-run: add TimerSlackNSec property

shell-completion: systemd-run: add SyslogFacility property

shell-completion: systemd-run: add SyslogLevel property

shell-completion: systemd-run: add new properties

shell-completion: systemd-run: add new properties See: * 602b83559a7cfcd3eee05 * b9c50073fcc1460ca1ff3

run: enable interactive authorization

shell-completion: update systemd-run bash completion Many new options have been added since the bash completion was last updated.

systemd-run: extend bash completion --system -H --host -M --machine --service-type (options: simple forking oneshot dbus notify idle) --uid --gid --nice --setenv -p --property (options read from bus_append_unit_property_assignment)

bash-completion: add systemd-run