Add local Debian package + plain binary build task

Adds packaging/local-build.sh and packaging/extract-binaries.sh, reused by a
new VS Code task, to populate gitignored dist/ and bin/ directories with the
same build.sh/test.sh/run.sh scripts the Gitea and GitHub workflows run.

.gitignore

@@ -1,3 +1,4 @@
 /.vscode/
 /dist/
+/bin/
 /distro.zip