DefaultUserHome: Local functionality

- AWS ParallelCluster version
3.14.2
- Full cluster configuration without any credentials or personal data.
- Cluster name:
rocky-pcluster

**Bug description and how to reproduce:**
DefaultUserHome: Local is described as: When set to Local, the head node, login nodes, and compute nodes will each have a separate local default user directory stored in local/home/.

This is true but /home is still being exported to the compute nodes and they mount it automatically. I need to use my own native NFS mount for /home on the headnode and all worker nodes via customization.

Can I disable the /home functionality and replace it like described? With enough finaggling I can probably get it working but I'd like the understand the intention of DefaultUserHome: Local. Side note: it is useful to have rocky user's home in local so i can't easily break connectivity via that user while messing with . /home so that is definitely one benefit

informational:
headnode
```$ cat /etc/exports
/home 10.95.0.0/21(rw,sync,no_root_squash)
/opt/parallelcluster/shared 10.95.0.0/21(rw,sync,no_root_squash)
/opt/parallelcluster/shared_login_nodes 10.95.0.0/21(rw,sync,no_root_squash)
/opt/intel 10.95.0.0/21(rw,sync,no_root_squash)
/mnt/ebs 10.95.0.0/21(rw,sync,no_root_squash)
/opt/slurm 10.95.0.0/21(rw,sync,no_root_squash)
```
```
$ find /local
/local
/local/home
/local/home/rocky
/local/home/rocky/.ssh
/local/home/rocky/.ssh/authorized_keys
/local/home/rocky/.ssh/id_ed25519
/local/home/rocky/.ssh/id_ed25519.pub
/local/home/rocky/.ssh/authorized_keys_cluster
/local/home/rocky/.ssh/known_hosts
/local/home/rocky/.bash_logout
/local/home/rocky/.bash_profile
/local/home/rocky/.bashrc
/local/home/rocky/.bash_history
```
compute
```
$ grep home /etc/fstab
10.95.1.129:/home /home nfs hard,_netdev,noatime 0 0
```

Start by tracing the DefaultUserHome: Local configuration and compare the generated /etc/exports entry on the head node with the compute node's /etc/fstab mount. Confirm whether disabling the shared /home export or replacing it with a custom NFS mount is supported, and document or implement the intended behavior with a reproducible validation path.

Written by the indexing model from the issue text.