avoid abs paths anywhere or bindmount them inside

comments on datalad runcmd commit record

```
commit 17f7919ab695ebcb101dd520743cd8ed9a5289de
...
"cmd": "duct --output-prefix $DUCT_PREFIX singularity run -B $PWD --pwd $PWD --containall --writable-tmpfs containers/images/bids/bids-mriqc--24.0.2.sif inputs/data/BIDS outputs/mriqc participant --no-datalad-get -w /scratch/f006rq8/job-8023140-250-sub-ON99881/ds/.git/tmp/wkdir --n_cpus 4 --mem_gb 16 -vv --no-sub --participant-label sub-ON99881",
```

Overall goal - -can you rerun this 1 commit locally or on typhon: just clone this repo and use 'datalad rerun --since 17f7919ab695ebcb101dd520743cd8ed9a5289de^ --to 17f7919ab695ebcb101dd520743cd8ed9a5289de ...'

possible solutions:

### 1 - bind mount inside into abs path

```
"cmd": "duct --output-prefix $DUCT_PREFIX singularity run -B $PWD -B $PWD/.git/scratch:/scratch --pwd $PWD --containall --writable-tmpfs containers/images/bids/bids-mriqc--24.0.2.sif inputs/data/BIDS outputs/mriqc participant --no-datalad-get -w /scratch/f006rq8/job-8023140-250-sub-ON99881/ds/.git/tmp/wkdir --n_cpus 4 --mem_gb 16 -vv --no-sub --participant-label sub-ON99881",
```

### 2 - more uniform - use $PWD there as well

```
"cmd": "duct --output-prefix $DUCT_PREFIX singularity run -B $PWD --pwd $PWD --containall --writable-tmpfs containers/images/bids/bids-mriqc--24.0.2.sif inputs/data/BIDS outputs/mriqc participant --no-datalad-get -w $PWD/.git/tmp/wkdir --n_cpus 4 --mem_gb 16 -vv --no-sub --participant-label sub-ON99881",
```