Add datetime stamp to simpeg.log and simpeg.out file names

[craigmillernz]

It would be useful to add a datetime stamp to the simpeg.log and simpeg.out file names so that multiple inversions can be run at the same time (on HPC for example) without overwriting the single simpeg.log / .out file. Desired fil name would be something like simpeg_09082023_120000.out (.log), which reflects the start date and time of the log file.

[github-actions]

JIRA issue [GEOPY-1029] was created.