Are an outlet and a light bulb at the main electrical panel required?
No
There's nothing in the NEC that demands a power outlet or switched light be installed by the panel. Indeed, some outdoor installations would make that impractical.
The caveat here is that a panel might be located somewhere that needs a GFCI outlet because of the location, not the presence of the panel. For instance, if your panel is in your basement (sometimes considered a wet zone), and you need an outlet in that room, it might be most economical to put an outlet like that next to the panel. Local codes might demand a light for the room as well.