Feature Request: `runtests.py --mode export_reproducer --to <x>` flag

[hagertnl]

I would like to see a feature in the OTH that can take an existing OTH test and create a standalone reproducer. This likely would require some guarantees by the test's build and run scripts to "follow best practices", but I envision it like this:

Given an OTH test that has a build script & Slurm template, this export_reproducer mode will:

1. fulfill the Slurm template replacements, using paths like ${PWD}/run_archive to fulfill the required paths for a test
2. copy the Source directory to the desired location
3. write a README file in this location describing the file layout, and how to run this reproducer.

This would greatly expedite getting issues reported.

[hagertnl]

Also remove calls to log_binary_execute.py, and replace check_executable.py with the command for the check script itself.