Buck: generate javadocs for plugin and extension API

  buck build api

generates now javadocs.

  buck build api_install

installs all plugin/extension related artifacts with javadocs in the
local Maven repository.

Change-Id: Ifa6a8eb469f388e16449576ff2bff01a5dce67dd

tools/maven/BUCK

diff --git a/tools/maven/BUCK b/tools/maven/BUCK
index 50b403b..9136db3 100644
--- a/tools/maven/BUCK
+++ b/tools/maven/BUCK
@@ -8,14 +8,19 @@
   url = 's3://gerrit-api@commondatastorage.googleapis.com/%s' % TYPE,
   version = GERRIT_VERSION,
   jar = {
-    'gerrit-extension-api': '//:extension-api',
-    'gerrit-plugin-api': '//:plugin-api',
-    'gerrit-plugin-gwtui': '//:plugin-gwtui',
+    'gerrit-extension-api': '//gerrit-extension-api:extension-api',
+    'gerrit-plugin-api': '//gerrit-plugin-api:plugin-api',
+    'gerrit-plugin-gwtui': '//gerrit-plugin-gwtui:gwtui-api',
   },
   src = {
-    'gerrit-extension-api': '//:extension-api-src',
-    'gerrit-plugin-api': '//:plugin-api-src',
-    'gerrit-plugin-gwtui': '//:plugin-gwtui-src',
+    'gerrit-extension-api': '//gerrit-extension-api:extension-api-src',
+    'gerrit-plugin-api': '//gerrit-plugin-api:plugin-api-src',
+    'gerrit-plugin-gwtui': '//gerrit-plugin-gwtui:gwtui-api-src',
+  },
+  doc = {
+    'gerrit-extension-api': '//gerrit-extension-api:extension-api-javadoc',
+    'gerrit-plugin-api': '//gerrit-plugin-api:plugin-api-javadoc',
+    'gerrit-plugin-gwtui': '//gerrit-plugin-gwtui:gwtui-api-javadoc',
   },
 )