Update supporting institutions

[cbrnr]

Our website contains logos of supporting institutions. We might want to update these once in a while, since contributors will change jobs from time to time. For example, I think AE Studio (which was added in #11695) should be removed, because Rob Luke does not work there anymore (according to his LinkedIn). There are probably other logos that should be changed/removed/updated.

This also raises the question of what criteria are used to determine whether an institution's logo should be included in the list of supporting institutions - maybe something for the soon to be established Steering Council to work out.

[sappelhoff]

I agree, see also:

• update governance #12896 (comment)