Add a dedicated page to the website for listing contributors

[sappelhoff]

similar to what MNE-Python has at the bottom of their landing page, but perhaps more detailed?

xrefs:

• Simplify license headers in source files mne-python#11605 (comment)

[cbrnr]

Yes! I think it (1) should be on a separate page (easier to cite if there is a dedicated URL, doesn't clutter the main page) and (2) should include more details, such as in https://github.com/all-contributors/all-contributors (they have roles which they display as emojis, maybe these roles can be consolidated/synced with roles in CITATION.cff).

[hoechenberger]

Great initiative