Set up embedded dev environment using PlatformIO

+keybindings.el

@@ -34,3 +34,10 @@
 ;; Keybindings for citar
 (map! :leader :n "n B" #'citar-open-files
       :desc "Open associated PDF with bibliography entry")
+;; Keybindings for PlatformIO
+(map! :after platformio-mode
+      :map platformio-mode-map
+      (:leader
+       :desc "Compile the project" "c c" #'platformio-build
+       :desc "Upload the project" "c u" #'platformio-upload
+       :desc "Monitor the serial console" "c m" #'platformio-device-monitor))