chore: gitignore build output (out/, dist/); untrack committed artifacts

Build artifacts had been committed by 'git add -A' after builds. Ignore and
untrack them; they are regenerated by the build.

Author: jthrilly

.gitignore

@@ -9,6 +9,10 @@
 /docs-build
 /plugins
 
+# Build output
+/out
+/dist
+
 npm-debug.log*
 yarn-debug.log*
 yarn-error.log*