Parallel execution fails

Each AWS region has a single namespace

Attempting to run multiple molecule test runs causes each run to clash with the other. Most obviously with the keypair.

This prevents molecule-ec2 being efficiently used as part of automated test pipelines.

Start at the molecule-ec2 execution path and inspect how each run creates and names its AWS resources, especially keypairs within a region. Reproduce two simultaneous molecule test runs and define done as both completing without namespace or keypair collisions.

Written by the indexing model from the issue text.