build: add a dune file

src/dune

+;; Time-stamp: <modified the 21/11/2021 (at 17:50) by Erwan Jahier>
+
+(executable
+ (name dot2lus)
+ (flags -noassert)
+  (link_flags (-linkall))
+ (libraries ocamlgraph lutils sasacore algo)
+)
+
+(install
+ (section bin)
+ (package sasa)
+ (files (dot2lus.exe as salut))
+; (files sasaRun.cmxa)
+)
+