Make Measurements Lazy

[acl-cqc]

• Extend Dataflow Analysis framework to allow lattice values for Sums (not just leaves thereof)
• Define lattice type (AbstractValue) with "DefiniteFuture" and "MaybeFuture" variants
• Propagate that through PolyFuncType "fype schemes" for ops to figure out their outputs as lattice values
• Transform Hugr - use previous to update TypeArgs for polymorphic ops; add coercions (Tag) when converting to MaybeFuture, read the Future when using a DefiniteFuture, case-split (and read) for MaybeFuture.

See also https://docs.rs/tket2-hseries/latest/tket2_hseries/extension/futures/index.html