Refactor LibraryPreprocessorBuilder class

Moved LibraryPreprocessorBuilder to its own file, `LibraryPreprocessorBuilder.cs`, and added a copyright header for 2025. Updated the namespace to `Hl7.Cql.Compiler.Preprocessing` for better organization. Retained the class functionality, including the constructor and `Build` method. Updated the copyright year in `LibraryPreprocessor.cs` to 2025.

Author: baseTwo

Cql/Cql.Compiler/Preprocessing/LibraryPreprocessor.cs

@@ -1,5 +1,5 @@
 /*
- * Copyright (c) 2024, Firely, NCQA and contributors
+ * Copyright (c) 2025, Firely, NCQA and contributors
  * See the file CONTRIBUTORS for details.
  *
  * This file is licensed under the BSD 3-Clause license
@@ -30,9 +30,4 @@ public void PreprocessLibrary(Library library)
         _missingResultTypeSpecifierCorrector.Fix(library);
         _profiledValueSetPropertyCorrector.Fix(library);
     }
-}
-
-internal class LibraryPreprocessorBuilder(ILoggerFactory loggerFactory)
-{
-    public LibraryPreprocessor Build(LibrarySet librarySet) => new(librarySet, loggerFactory);
 }

Cql/Cql.Compiler/Preprocessing/LibraryPreprocessorBuilder.cs

@@ -0,0 +1,14 @@
+/*
+ * Copyright (c) 2025, Firely, NCQA and contributors
+ * See the file CONTRIBUTORS for details.
+ *
+ * This file is licensed under the BSD 3-Clause license
+ * available at https://raw.githubusercontent.com/FirelyTeam/firely-cql-sdk/main/LICENSE
+ */
+
+namespace Hl7.Cql.Compiler.Preprocessing;
+
+internal class LibraryPreprocessorBuilder(ILoggerFactory loggerFactory)
+{
+    public LibraryPreprocessor Build(LibrarySet librarySet) => new(librarySet, loggerFactory);
+}