This is better than setting an environment variable like
TOOLBOX_CONTAINER with 'podman create' because, unlike environment
variables, it can't be unset later by commands like su(1) or sudo(8).
One nice side-effect of doing it inside 'toolbox enter' is that it
will automatically work with older toolbox containers.
A subsequent commit will switch to using the /etc/profile.d/toolbox.sh
start-up script to set the PS1 instead of doing it as part of the
'podman exec' invocation. Having the identification mechanism work with
older toolbox containers is important to avoid breaking the PS1 for
backwards compatibility.
This reverts commit c7b7fa1867https://github.com/debarshiray/toolbox/pull/148
This is a lot more clear and explicit than TOOLBOX_PATH, which is more
of an implementation detail to bind mount the toolbox script inside the
toolbox container.
https://github.com/debarshiray/toolbox/pull/142
