uudecode: add page (#5971)

pages/common/uudecode.md

@@ -0,0 +1,12 @@
+# uudecode
+
+> Decode files encoded by `uuencode`.
+> More information: <https://manned.org/uudecode>.
+
+- Decode a file that was encoded with `uuencode` and print the result to stdout:
+
+`uudecode {{path/to/encoded_file}}`
+
+- Decode a file that was encoded with `uuencode` and write the result to a file:
+
+`uudecode -o {{path/to/decoded_file}} {{path/to/encoded_file}}`