Feature request: auto-detect Sockets and CoresPerSocket

Parallel Cluster to automatically detect the correct number of sockets and cores-per-socket in Slurm partitions.

Basically, to automate the solution in #5797 so that users do not need to figure out themselves the number of sockets. AFAIK, the number of sockets is not in public EC2 documentations, and would require users to run an instance just to find out the value.

**Required Info:**
- AWS ParallelCluster version [e.g. 3.1.1]: 3.8.0

Start by reading issue #5797 and the Slurm partition configuration flow, then investigate how AWS instance socket and core values could be detected without requiring users to run an instance. Done means Parallel Cluster automatically supplies the correct sockets and cores-per-socket for Slurm partitions.

Written by the indexing model from the issue text.