Update logo in header to svg

[jochemvogel]

Description

Closes #253

Type of change

Please select the option that is relevant

• [ ] Bug fix (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

Checklist

• [x] I have commented my code, particularly in hard-to-understand areas.
• [x] All the required documentation is added.
• [x] My code follows the style guidelines of this project.
• [x] I have performed a self-review of my own code.

Additional information

[Provided extra information if necessary]

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