feat: Use new versioning strategy

- Rename BuildHash to SCMVersion
- Expose the actual commit hash as a new `commit_hash.txt`
- Update GetGitHash() to actually return the git hash

Dalamud/EntryPoint.cs

@@ -185,7 +185,7 @@ public sealed class EntryPoint
 
             var dalamud = new Dalamud(info, fs, configuration, mainThreadContinueEvent);
             Log.Information("This is Dalamud - Core: {GitHash}, CS: {CsGitHash} [{CsVersion}]", 
-                            Util.GetGitHash(), 
+                            Util.GetScmVersion(), 
                             Util.GetGitHashClientStructs(), 
                             FFXIVClientStructs.ThisAssembly.Git.Commits);