Bloom filter use pk_prefix instead of distribution_key

[wcy-fdu]

Perviously, we use distribution_key as our bloom filter key, and distribution_key is always the prefix of pk. After watermark design, we can not ensure the distribution key be the prefix of pk(#6288), so #6575 has changed the prefix_hint to dist_key_hint for bloom_filter.
However, using distribution key as bloom filter key will make things more complex, for example: we need to handle many corner cases, such as shuffled distribution key and discontinuous distribution key. And we need to intercept distribution key from pk, and do many judgement in StateTable/StorageTable/FilterKeyExtract.

After some discussion, we can decouple bloom filter key and distribution key, just use pk prefix as the bloom filter key, this makes things easier and bloom filter will be used in more places.

• add prefix_len in catalog
• change bloom filter key from distribution key to pk prefix

[wcy-fdu]

cc @hzxa21 @Li0k