mkfile: move to common (#9585)

pages/common/mkfile.md

@@ -0,0 +1,16 @@
+# mkfile
+
+> Create one or more empty files of any size.
+> More information: <https://manned.org/mkfile>.
+
+- Create an empty file of 15 kilobytes:
+
+`mkfile -n {{15k}} {{filename}}`
+
+- Create a file of a given size and unit (bytes, KB, MB, GB):
+
+`mkfile -n {{size}}{{b|k|m|g}} {{filename}}`
+
+- Create two files of 4 megabytes each:
+
+`mkfile -n {{4m}} {{first_filename}} {{second_filename}}`