move Var/Lit/Pol into separate lit crate

These types have plenty of use cases that don't depend on specific IR
data structures, so it should be possible to depend on them without
pulling in the `ir` crate as dependency.

Author: jix

Cargo.lock

@@ -15,6 +15,7 @@ members = [
     "inc_refine",
     "extract",
     "imctk",
+    "lit",
 
     # comment to force multi-line layout
 ]

Cargo.toml

@@ -15,6 +15,7 @@ hashbrown = { version = "0.14.5", default-features = false, features = [
 ] }
 imctk-derive = { version = "0.1.0", path = "../derive" }
 imctk-ids = { path = "../ids" }
+imctk-lit = { version = "0.1.0", path = "../lit" }
 imctk-transparent = { version = "0.1.0", path = "../transparent" }
 imctk-util = { version = "0.1.0", path = "../util" }
 log = "0.4.21"