relative paths for jupyter integration and esm-tools

[pgierz]

Summary

• Use relative paths for logo, figures, and notebooks in generated HTML
• Compute paths dynamically based on configured output directories

Changes

tripyview/sub_tripyrun.py:

• Copy fesom2_logo.png to output directory instead of referencing it from the package location
• Use relative path ./fesom2_logo.png instead of absolute path

tripyview/sub_tripyrundriver.py:

• Replace hardcoded ./figures/ and ./notebooks/ paths with dynamically computed relative paths using os.path.relpath()
• Paths are now computed relative from save_path (HTML location) to tripyrun_spath_fig and tripyrun_spath_nb

Why

The generated HTML previously used absolute paths for the logo and assumed figures/notebooks were always in ./figures/ and ./notebooks/ subdirectories. This broke when:

1. Opening the HTML in a browser (absolute paths don't resolve)
2. Using custom figure_dir or notebook_dir settings in the YAML config

Backward Compatibility

Fully backward-compatible. When using default settings (no custom figure_dir/notebook_dir), the computed relative paths produce the same ./figures/ and ./notebooks/ paths as before.