- Remove `cur_score` from `Bucket`
- Switch benchmark to LRU strategy

On pure HBM mode

1. Using digests(some bits of hashed keys) as a filter to reduce memory
traffic.
2. Using kernel level pipeline to overlap memory accesses to hide
latency.
3. Unit test of the look kernels using filter and pipeline.
4. Make dim which lookup kernel with pipeline support Configurable.
5. Put common kernels into the core_kernels folder, and modify the BUILD file used for bazel build.
6. Change the way addressing digests
7. When init hash table, check the bucket_max_size to make keys and scores meet cache line size.

- Fix a little potential bug for exporting RECLAIM KEYS
- Some name refactoring

- Add strategy check in `insert_and_evict`