[Aaru.Filesystems] Introduced constants for module names

Introduces constant fields for respective debug module names, replacing the hardcoded ones.
This is done to standardize the naming convention, reduce redundancy and potentially avoid any typos or name mismatches across the project.
This change makes the code more maintainable and easier to update in case module names need to be changed.

Aaru.Filesystems/UNICOS/Info.cs

@@ -72,7 +72,7 @@ public sealed partial class UNICOS
 
         Superblock unicosSb = Marshal.ByteArrayToStructureBigEndian<Superblock>(sector);
 
-        AaruConsole.DebugWriteLine("UNICOS plugin", Localization.magic_equals_0_expected_1, unicosSb.s_magic,
+        AaruConsole.DebugWriteLine(MODULE_NAME, Localization.magic_equals_0_expected_1, unicosSb.s_magic,
                                    UNICOS_MAGIC);
 
         return unicosSb.s_magic == UNICOS_MAGIC;

Aaru.Filesystems/UNICOS/UNICOS.cs

@@ -49,4 +49,5 @@ public sealed partial class UNICOS : IFilesystem
     public Guid Id => new("61712F04-066C-44D5-A2A0-1E44C66B33F0");
     /// <inheritdoc />
     public string Author => Authors.NataliaPortillo;
+    const string MODULE_NAME = "UNICOS plugin";
 }