add doc, rename server.ml to osh.ml

doc/dune

+(documentation
+ (package osh)
+ (mld_files index))

doc/index.mld

+{0 osh}
+
+{{:https://osh.ocamlpro.com} osh} is an {{:https://ocaml.org} OCaml} website providing an API to generate SVG badges.
+
+{1:webapi Web API}
+
+See the documentation on the {{:https://osh.ocamlpro.com} online instance}.
+
+
+{1:modules Modules}
+
+You shouldn't have to use any of these modules, they're used internally only.
+
+{!modules:
+Osh.Content
+Osh.Server
+Osh.Template
+}

src/dune

 (executable
- (name server)
- (modules content server template)
+ (public_name osh)
+ (modules content osh template)
  (libraries dream ezcurl ocb omd yojson))
 
 (rule