llama-bench: add --devices and --list-devices support (#16039)

llama-bench: add --devices and --list-devices support (#16039)

* * llama-bench: add --devices support
- Support --devices same as llama-server
- Provide for benchmarking different device combinations
- Include --list-devices like llama-server for convenience

* fix: field display ordering restored

* fix: integrated the rpc devices
- aimed to mimic the server as much as possible

* cleanup: defaults for list-devices
- handle dup device listing with RPC

* cleanup: remove dup device load calls

* docs: update llama-bench
- added the recently added n-cpu-moe option to the docs while in there

* llama-bench: rpc device simplification
* rpc servers unify with other devices earlier, simplifying code
* --list-devices made stateless and simpler
* various cleanup