Add opam-graph, modulectomy packages

Remove pin-depends in builder-web and add new package opam-graph and
update modulectomy branch.

packages/builder-web.0.2.0~dev/opam

@@ -59,10 +59,6 @@ Produced binaries can be downloaded and executed.
 [builds.robur.coop](https://builds.robur.coop/) itself runs builder-web.
 """
 
-pin-depends: [
-  ["modulectomy.dev" "git+https://github.com/roburio/modulectomy.git#20211213_implementing_UI_scale_in_modulectomy.treemap"]
-  ["opam-graph.dev" "git+https://git.robur.io/robur/opam-graph.git"]
-]
 url {
   src: "git+https://git.robur.io/robur/builder-web.git"
 }

packages/modulectomy.0.0.1~dev/opam

@@ -27,5 +27,5 @@ build: [
 ]
 dev-repo: "git+https://github.com/Drup/modulectomy.git"
 url {
-  src: "git+https://github.com/roburio/modulectomy.git"
+  src: "git+https://github.com/roburio/modulectomy.git#20211213_implementing_UI_scale_in_modulectomy.treemap"
 }

packages/opam-graph.0.1.0~dev/opam

@@ -0,0 +1,34 @@
+opam-version: "2.0"
+maintainer: "Robur <team@robur.coop>"
+authors: ["Robur <team@robur.coop>"]
+homepage: "https://git.robur.io/robur/opam-graph"
+dev-repo: "git+https://git.robur.io/robur/opam-graph.git"
+bug-reports: "https://github.com/roburio/opam-graph/issues"
+license: "ISC"
+
+depends: [
+  "ocaml" {>= "4.08.0"}
+  "dune" {>= "2.0.0"}
+  "cmdliner"
+  "fmt" {>= "0.8.7"}
+  "logs"
+  "opam-core"
+  "opam-format"
+  "ocamldot"
+  "rresult"
+  "tyxml"
+  "gg"
+]
+build: [
+  ["dune" "subst"] {dev}
+  ["dune" "build" "-p" name "-j" jobs]
+]
+
+synopsis: "Graphing dependencies of opam packages"
+description: """
+This package outputs graphs (in svg and dot) of opam packages.
+"""
+
+url {
+  src: "git+https://git.robur.io/robur/opam-graph.git"
+}