Refactor GenerateStablePackages (#9744)

* Refactor GenerateStablePackages

Summary of changes:

* Split GenerateStablePackages executable into a library (containing the stable package data) and an executable (that writes out the packages)

* Hook up data-dependencies test to the new library so we don't have to manually update the number of stable packages every time we add a stable package or release a new LF version.

changelog_begin
changelog_end

* buildifier-fix

compiler/damlc/stable-packages/BUILD.bazel

@@ -1,23 +1,42 @@
 # Copyright (c) 2021 Digital Asset (Switzerland) GmbH and/or its affiliates. All rights reserved.
 # SPDX-License-Identifier: Apache-2.0
 
-load("//bazel_tools:haskell.bzl", "da_haskell_binary")
+load("//bazel_tools:haskell.bzl", "da_haskell_binary", "da_haskell_library")
+
+da_haskell_library(
+    name = "stable-packages-lib",
+    srcs = glob(["lib/**/*.hs"]),
+    hackage_deps = [
+        "base",
+        "bytestring",
+        "containers",
+        "text",
+    ],
+    visibility = ["//visibility:public"],
+    deps = [
+        "//compiler/daml-lf-ast",
+        "//compiler/daml-lf-proto",
+        "//compiler/damlc/daml-lf-conversion",
+        "//libs-haskell/da-hs-base",
+    ],
+)
 
 da_haskell_binary(
     name = "generate-stable-package",
     srcs = glob(["src/**/*.hs"]),
     hackage_deps = [
         "base",
         "bytestring",
+        "containers",
         "optparse-applicative",
         "text",
     ],
     main_function = "GenerateStablePackage.main",
     visibility = ["//visibility:public"],
     deps = [
+        ":stable-packages-lib",
         "//compiler/daml-lf-ast",
         "//compiler/daml-lf-proto",
-        "//compiler/damlc/daml-lf-conversion",
         "//libs-haskell/da-hs-base",
     ],
 )