Should have top-level groups for the IESG and IRTF

[paulehoffman]

Description

In the "Groups" menu in the Datatracker, there is a top-level group for the IAB (https://datatracker.ietf.org/group/iab/about/), but not for the IESG or IRTF. Even just pointers to the IESG and IRTF home pages would be useful, but a page like the IAB top-level group would be more helpful.

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