[k3d-dev.sh] using gp3 and volume encryption

General MR

Summary

This swaps out GP2 for GP3 volumes on the k3d-dev.sh script. This results in a 20% cost savings and also gives each volume a baseline of 3000 Iops and 125 MiB/s throughput for free. It also enables volume encryption.

Relevant logs/screenshots

N/A