Migrate dev:setup to standalone script

mise-tasks/dev/setup

@@ -0,0 +1,17 @@
+#!/usr/bin/env bash
+
+#MISE description="Setup the local development environment"
+
+set -e
+
+# Add the Fluxon UI hex source repo
+
+mix hex.repo add fluxon https://repo.fluxonui.com \
+  --fetch-public-key $FLUXON_KEY_FINGERPRINT \
+  --auth-key $FLUXON_LICENSE_KEY
+
+# Install the gh extension to preview local markdown files
+
+gh extension install thiagokokada/gh-gfm-preview
+
+mix setup