Implement environment variable REFL1D_JOB_SUB_DIR.

Zhou, Wenduorequested to merge
configure_output_269 into next

This fixes https://code.ornl.gov/sns-hfir-scse/reflectometry/reflectometry/-/issues/284.

The work is to use REFL1D_JOB_SUB_DIR to replace hard coded reflectivity_fit in the directory name to output fitting result.

Edited by Zhou, Wenduo

Merge request reports