tons of environment variables

HPK generates tons of environmental variables.

In Docker:
```
SHLVL=1
TERM=xterm
_=/usr/bin/env
K_MPI_JOB_ROLE=worker

HOME=/root
HOSTNAME=pi-worker-0
PWD=/home/mpiuser
PATH=/usr/local/sbin:/usr/local/bin:/usr/sbin:/usr/bin:/sbin:/bin

KUBERNETES_PORT_443_TCP_ADDR=10.152.183.1
KUBERNETES_PORT_443_TCP_PORT=443
KUBERNETES_PORT_443_TCP_PROTO=tcp
KUBERNETES_PORT_443_TCP=tcp://10.152.183.1:443
KUBERNETES_PORT=tcp://10.152.183.1:443
KUBERNETES_SERVICE_HOST=10.152.183.1
KUBERNETES_SERVICE_PORT=443
KUBERNETES_SERVICE_PORT_HTTPS=443
```

In HPK (Manually grouped):
```
K_MPI_JOB_ROLE=worker
IFS=
LANG=C
LOGNAME=mpiuser
OPTIND=1
SHELL=/bin/sh
TERM=screen-256color
USER=mpiuser
PROMPT_COMMAND=PS1="Apptainer> "; unset PROMPT_COMMAND
PS1=Apptainer>

PWD=/root
HOME=/home/mpiuser
LD_LIBRARY_PATH=:/.singularity.d/libs
LD_PRELOAD=/.singularity.d/libs/libfakeroot.so
PATH=/usr/local/sbin:/usr/local/bin:/usr/sbin:/usr/bin:/sbin:/bin

APPTAINER_APPNAME=
APPTAINER_BIND=/home/mpiuser/.ssh,.hpk/default/pi-worker-0/.virtualenv/kube-api-access-688cm:/home/mpiuser/.ssh,.hpk/default/pi-worker-0/.virtualenv/kube-api-access-688cm:/var/run/secrets/kubernetes.io/serviceao
APPTAINER_COMMAND=exec
APPTAINER_CONTAINER=/root/.apptainer/cache/oci-tmp/87bb28d964b0c1fc28438552e85e7a6236060cba31ac1996bc3b9376e1855a79
APPTAINER_ENVIRONMENT=/.singularity.d/env/91-environment.sh
APPTAINER_NAME=87bb28d964b0c1fc28438552e85e7a6236060cba31ac1996bc3b9376e1855a79
APPTAINER_NO_EVAL=1

FAKED_MODE=unknown-is-root
FAKEROOTDONTTRYCHOWN=1
FAKEROOTEGID=1000
FAKEROOTEUID=1000
FAKEROOTFGID=1000
FAKEROOTFUID=1000
FAKEROOTGID=1000
FAKEROOTKEY=674349507
FAKEROOTSGID=1000
FAKEROOTSUID=1000
FAKEROOTUID=1000

KUBERNETES_PORT_443_TCP_ADDR=10.244.5.56
KUBERNETES_PORT_443_TCP_PORT=443
KUBERNETES_PORT_443_TCP_PROTO=tcp
KUBERNETES_PORT_443_TCP=tcp://10.244.5.56:443
KUBERNETES_PORT=tcp://10.244.5.56:443
KUBERNETES_SERVICE_HOST=10.244.5.56
KUBERNETES_SERVICE_PORT=443
KUBERNETES_SERVICE_PORT_HTTPS=443

SINGULARITY_BIND=/home/mpiuser/.ssh,.hpk/default/pi-worker-0/.virtualenv/kube-api-access-688cm:/home/mpiuser/.ssh,.hpk/default/pi-worker-0/.virtualenv/kube-api-access-688cm:/var/run/secrets/kubernetes.io/servico
SINGULARITY_CONTAINER=/root/.apptainer/cache/oci-tmp/87bb28d964b0c1fc28438552e85e7a6236060cba31ac1996bc3b9376e1855a79
SINGULARITY_ENVIRONMENT=/.singularity.d/env/91-environment.sh
SINGULARITY_NAME=87bb28d964b0c1fc28438552e85e7a6236060cba31ac1996bc3b9376e1855a79
SINGULARITY_NO_EVAL=1
```