Add Code Action for adding a module to the cabal file

For diagnostics complaining about the current module being unknown,
we now offer code actions to add the module to any possible field in
the responsible cabal file.

Additionally, refactor the cabal-plugin into smaller modules and
refactor the add-package feature to have some shared functions to be
used for both add-package and add-module.

Author: VeryMilkyJoe

cabal.project

@@ -6,6 +6,7 @@ packages:
          ./ghcide
          ./hls-plugin-api
          ./hls-test-utils
+         ../cabal-add
 
 
 index-state: 2025-06-07T14:57:40Z

haskell-language-server.cabal

@@ -254,8 +254,13 @@ library hls-cabal-plugin
     Ide.Plugin.Cabal.Completion.Types
     Ide.Plugin.Cabal.Definition
     Ide.Plugin.Cabal.FieldSuggest
+    Ide.Plugin.Cabal.Files
+    Ide.Plugin.Cabal.OfInterest
     Ide.Plugin.Cabal.LicenseSuggest
-    Ide.Plugin.Cabal.CabalAdd
+    Ide.Plugin.Cabal.Rules
+    Ide.Plugin.Cabal.CabalAdd.Command
+    Ide.Plugin.Cabal.CabalAdd.CodeAction
+    Ide.Plugin.Cabal.CabalAdd.Types
     Ide.Plugin.Cabal.Orphans
     Ide.Plugin.Cabal.Outline
     Ide.Plugin.Cabal.Parse
@@ -276,14 +281,14 @@ library hls-cabal-plugin
     , lens
     , lsp                   ^>=2.7
     , lsp-types             ^>=2.3
+    , mtl
     , regex-tdfa            ^>=1.3.1
     , text
     , text-rope
     , transformers
     , unordered-containers  >=0.2.10.0
     , containers
     , cabal-add
-    , process
     , aeson
     , Cabal
     , pretty
@@ -315,7 +320,6 @@ test-suite hls-cabal-plugin-tests
     , lens
     , lsp-types
     , text
-    , hls-plugin-api
 
 -----------------------------
 -- class plugin