Add summary listing for subprojects #254
Description
Right now, subprojects that host their blogs here may want to link to a listing with summary, but those are non-existent. E.g., matplotlib links to their tag, but the tags pages do not have summaries.
I suggest we add summary listings to https://blog.scientific-python.org/ so that projects can link there directly, and so they do not have to link to all posts that use their project name as a tag.