[Discuss][C++] Replace MemoTable with a SwissTable implementation

### Describe the enhancement requested

This is a follow up of https://github.com/apache/arrow/issues/36059#issuecomment-1592037527. There are many cases where we use a `MemoTable`, e.g. set lookup functions, vector hash functions, the `count_distinct` aggregate function, dictionary unification etc. Their performance can be boosted with a SwissTable.

We can either:
1. Use an existing swiss table library. This requires some work on dependency management. I recommend `absl::flat_hash_map` since they are the original author of swiss tables and we already has `absl` in our 3rd party toolchain.
2. Write one by ourselves. The current one in `acero` is too customized for the join node and it seems hard to extract a general hashtable from it. If I were to write one I would probably follow the structure of `absl`'s and replace things like memory management and bit tweaking with Arrow ones.

What do you think? @pitrou @westonpace

### Component(s)

C++