docs: Add GUI.md

Change-Id: Ic7ffb8dea4521af95cb87e578be3eb46af6e8f6e
diff --git a/docs/img/gui/file-dropdown.png b/docs/img/gui/file-dropdown.png
new file mode 100644
index 0000000..9e0354c
--- /dev/null
+++ b/docs/img/gui/file-dropdown.png
Binary files differ