[Feature Request]: Add support for a directory to run custodian calculations with

[Andrew-S-Rosen]

Problem

Pretty much across the board, Custodian assumes that everything is being done in the local working directory. Oftentimes, this is fine because the user will typically have the calculation run in an isolated location. However, if trying to run calculations in a multi-threaded mode (or any mode where you run multiple calculations per Python process), this can get messy really quickly because you can't call os.chdir in such scenarios.

Ideally, the various handlers should take an optional directory: str | Path = "." keyword argument, which is then used for all I/O and in the subprocess call to the executable.

Proposed Solution

Lots of manual insertion of directory before filenames and in subprocess.

Alternatives

No response