updates to experiment_runner.py

[1andrin]

updates to experiment_runner.py to improve the plot design and to add auto-detection of the current case.

Problem

• plots were not suitable for use in a paper
• CATE plots only showed results for metrics included in the --metrics argument while the MSE plots were always created for all available metrics in the results file
• case (e.g. RCT or KC or KCKP) had to be set manually in the main() loop

Proposed changes

• make some design changes and add font_size parameter that can be set in single location in code.
• also plot everything available for CATE plots
• add case detection based on the the --dataset argument

Types of changes

What types of changes does your code introduce to causaltune?
Put an x in the boxes that apply

• [x ] Bugfix (non-breaking change which fixes an issue)
• [x ] New feature (non-breaking change which adds functionality)
• Breaking change (fix or feature that would cause existing functionality to not work as expected)
• Documentation Update (if none of the other choices apply)

Checklist

• I have read the CONTRIBUTING doc
• Description above provides context of the change
• I have added tests that prove my fix is effective or that my feature works
• Unit tests for changes (not needed for documentation changes)
• Bumping version in setup.py is an individual PR and not mixed with feature or bugfix PRs
• Commits follow "How to write a good git commit message"
• Relevant documentation is updated including usage instructions