Add RVV qs8/qu8 gavgpool kernels, configs and tests.

[oliIMG]

[dsharlet]

We are currently working on deprecating gavgpool and replacing it with static_mean, which is a generalization of gavgpool. I suggest directing your efforts towards implementing rsum and rdsum (which implement static_mean) rather than gavgpool.

[ken-unger]

This PR is obsolete and should be closed