…erenceUtils

The main debugging function is
`TypeInferenceUtils::dumpAllState(mlir::Operation* op)` which dumps
the entire state of type inference for the function containing `op`.

This adds a new dialect called `Optimizer` with operations related to
the Concrete Optimizer. Currently, there is only one operation
`optimizer.partition_frontier` that can be inserted between a producer
and a consumer which belong to different partitions computed by the
optimizer. The purpose of this operation is to preserve explicit key
changes from the invocation of the optimizer on high-level dialects
(i.e., FHELinalg / FHE) until the IR is provided with actual
references to keys in low-level dialects (i.e., TFHE).

… to std

…gh the pipeline

The Concrete Optimizer is invoked on a representation of the program
in the high-level FHELinalg / FHE Dialects and yields a solution with
a one-to-one mapping of operations to keys. However, the abstractions
used by these dialects do not allow for references to keys and the
application of the solution is delayed until the pipeline reaches a
representation of the program in the lower-level TFHE dialect. Various
transformations applied by the pipeline along the way may break the
one-to-one mapping and add indirections into producer-consumer
relationships, resulting in ambiguous or partial mappings of TFHE
operations to the keys. In particular, explicit frontiers between
optimizer partitions may not be recovered.

This commit preserves explicit frontiers between optimizer partitions
as `optimizer.partition_frontier` operations and lowers these to
keyswitch operations before parametrization of TFHE operations.

…ntiers

…optimization