Add HALO/DaCapo frontend to HEIR

Related: https://github.com/google/heir/issues/289

DaCapo / HALO are also MLIR based compilers, and they define an EARTH dialect, and then optimize it and create a CKKS dialect. It would be great to add a translation from their optimized CKKS dialect to a HEIR dialect. I think their CKKS dialect is fairly similar to ours, so it might be possible to just write an importer directly into the CKKS dialect?

Their dialect already includes modswitch and noise management operations, but I don't know how that will interact with us lowering to the Openfhe backend (whether the parameters selected with Openfhe will be compatible)