[bazel] Colocate Doxygen version declarations (#8806)

Since we currently have both a Bazel build and Gradle build, we need to
keep the Doxygen versions in sync between the two.


40188d9cc6/docs/build.gradle (L71)

It's awkward that these are in very disjoint parts of the repo. This
puts them in the same directory so it's more obvious it should be kept
in sync.

MODULE.bazel

@@ -3,6 +3,8 @@ module(
     version = "0.0.0",
 )
 
+include("//docs:doxygen.MODULE.bazel")
+
 bazel_dep(name = "apple_support", version = "2.0.0", repo_name = "build_bazel_apple_support")
 
 # TODO(austin): Upgrade when the patches land.
@@ -76,32 +78,6 @@ maven.install(
 use_repo(maven, "maven", "unpinned_maven")
 
 bazel_dep(name = "caseyduquettesc_rules_python_pytest", version = "1.1.1", repo_name = "rules_python_pytest")
-bazel_dep(name = "rules_doxygen", version = "2.5.0")
-archive_override(
-    module_name = "rules_doxygen",
-    integrity = "sha256-qxfKreTkQnV4tUX6KJDFXuOJj4p6VZdBYjAie77I5ho=",
-    strip_prefix = "rules_doxygen-2.5.0",
-    urls = ["https://github.com/TendTo/rules_doxygen/releases/download/2.5.0/rules_doxygen-2.5.0.tar.gz"],
-)
-
-doxygen_extension = use_extension("@rules_doxygen//:extensions.bzl", "doxygen_extension")
-doxygen_extension.configuration(
-    platform = "windows",
-    sha256 = "44658b9cc5c91749e6e3cc426ba63e2550b4a4a7619065acd77029aa234719c6",
-    version = "1.15.0",
-)
-doxygen_extension.configuration(
-    platform = "mac",
-    sha256 = "b7630eaa0d97bb50b0333929ef5dc1c18f9e38faf1e22dca3166189a9718faf0",
-    version = "1.15.0",
-)
-doxygen_extension.configuration(
-    platform = "linux",
-    sha256 = "0ec2e5b2c3cd82b7106d19cb42d8466450730b8cb7a9e85af712be38bf4523a1",
-    version = "1.15.0",
-)
-use_repo(doxygen_extension, "doxygen")
-
 bazel_dep(name = "eigen", version = "5.0.1")
 local_path_override(
     module_name = "eigen",