nano-ffmpeg: add page (#22163)

Co-authored-by: Ivan Baluta <ivanbaluta.dev@gmail.com>

pages/common/nano-ffmpeg.md

@@ -0,0 +1,28 @@
+# nano-ffmpeg
+
+> A wrapper for `ffmpeg` with an interactive file browser and operations.
+> More information: <https://github.com/dgr8akki/nano-ffmpeg#usage>.
+
+- Start `nano-ffmpeg`:
+
+`nano-ffmpeg`
+
+- Open the file picker at a specific directory:
+
+`nano-ffmpeg {{[-d|--dir]}} {{path/to/directory}}`
+
+- Open a specific file directly:
+
+`nano-ffmpeg {{[-d|--dir]}} {{path/to/file.ext}}`
+
+- Override the theme for the current session:
+
+`nano-ffmpeg {{[-t|--theme]}} {{dark|light}}`
+
+- Exit `nano-ffmpeg`:
+
+`<q>`
+
+- Display help:
+
+`nano-ffmpeg {{[-h|--help]}}`