DEV: Introduce syntax_tree code formatter (#19775)

This commit introduces the necessary gems and config, but adds all our ruby code directories to the `--ignore-files` list.

Future commits will apply syntax_tree to parts of the codebase, removing the ignore patterns as we go

.streerc

@@ -1,2 +1,10 @@
 --print-width=100
---plugins=plugin/trailing_comma
+--plugins=plugin/trailing_comma,disable_ternary
+--ignore-files=Gemfile
+--ignore-files=app/*
+--ignore-files=config/*
+--ignore-files=db/*
+--ignore-files=lib/*
+--ignore-files=plugins/*
+--ignore-files=script/*
+--ignore-files=spec/*