feat(medusa): Allow logging to file (#4696)

* enable additional log transport to file if FILE_NAME env var is set

* change var declaration to const

* Create chilly-geckos-look.md

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Co-authored-by: Oli Juhl <59018053+olivermrbl@users.noreply.github.com>

.changeset/chilly-geckos-look.md

@@ -0,0 +1,6 @@
+---
+"@medusajs/medusa": patch
+"@medusajs/medusa-cli": patch
+---
+
+Feat/allow logging to file