Resolve "Prepare package for installation"

Closes #25

See merge request ag-hydinf/boog-group/r2ogs6!20

# Conflicts:
#   .gitignore
#   R/ogs6_ensemble.R
#   R/zzz.R
#   vignettes/ensemble_workflow_vignette.Rmd

Resolve "update paths to ogs6-BM files in ensemble vignette"

Closes #30

See merge request ag-hydinf/boog-group/r2ogs6!18

Resolve "define ogs6 executable explicitly and add option for using singularioty containers"

Closes #26

See merge request ag-hydinf/boog-group/r2ogs6!17

    set ogs executables explicitly instead of ogs bin folder path
    add option to use ogs singularity containers

Resolve "Add overwrite flag to run_simulation function"

Closes #27

See merge request ag-hydinf/boog-group/r2ogs6!15

Resolve "edit vignette for theis problem"

Closes #24

See merge request ag-hydinf/boog-group/r2ogs6!14