Print text without buffering

[sumiya-kuroda]

Description

What is this PR

• Bug fix
• Addition of a new feature
• Other

Why is this PR needed?
Right now, Python's print is buffered, which makes it difficult to understand what the pipeline is doing in real-time. For example, suite2p's output is lagged and difficult to assess the progress.

What does this PR do?
This adds an option to change the environment variable PYTHONUNBUFFERED. One can call photon-mosaic like below and it prints the output immediately.

PYTHONUNBUFFERED=1 photon-mosaic

Checklist:

• The code has been tested locally
• Tests have been added to cover all new functionality
• The documentation has been updated to reflect any changes
• The code has been formatted with pre-commit

[lauraporta]

This sounds like a good idea, I didn't know of PYTHONUNBUFFERED. I will leave some comments.

[lauraporta]

I am curious of what happens with buffering when running multiple jobs in parallel. Will the print statement be included in a chronological order? That will make debugging harder. To be investigated.