CANN: implement LRU cache for ACL graphs (llama/15814)

CANN: implement LRU cache for ACL graphs (llama/15814)

* CANN: implement LRU cache for ACL graphs in CANN backend

- Introduce ggml_cann_graph_lru_cache to store multiple ggml_cann_graph objects.
- Graphs are loaded on demand and evicted using LRU policy when capacity is exceeded.
- Updated push, move_to_front, and clear methods to manage cached graphs efficiently.
- Ensures reuse of graphs, reducing graph reconstruction overhead in CANN backend.

* fix typo

* The LRU cache capacity can be configured via an env variable

Signed-off-by: noemotiovon <redacted>
* refactory acl graph

* refactory && fix review comments

Signed-off-by: noemotiovon <redacted>
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Signed-off-by: noemotiovon <redacted>