Add links to rocks docs

Author: patiencedaur

doc/reference/reference_rock/expirationd.rst

@@ -1,18 +1,21 @@
 :noindex:
 :fullwidth:
 
-================================================================================
 Rocks reference
-================================================================================
+===============
 
 This reference covers third-party Lua modules for Tarantool.
 
-.. toctree::
-    :maxdepth: 2
+..  toctree::
+    :maxdepth: 1
 
-    dbms
-    expirationd
+    ../../book/cartridge/index
     membership
+    ../../book/monitoring/metrics_reference
+    Module luatest <luatest/luatest_overview>
     vshard/index
-    ../../book/cartridge/index
-    luatest/luatest_overview
+    dbms
+    other
+
+For Tarantool Enterprise modules, see the
+`Tarantool Enterprise documentation <https://www.tarantool.io/en/enterprise_doc/rocksref/>`_.

doc/reference/reference_rock/index.rst

@@ -0,0 +1,14 @@
+Other rocks
+===========
+
+This page features a list of links to third-party Tarantool module documentation
+that is hosted externally -- mostly on GitHub pages or in READMEs:
+
+*   checks <https://github.com/tarantool/checks/#readme>
+*   crud <https://github.com/tarantool/crud#readme>
+*   expirationd <https://tarantool.github.io/expirationd/>
+*   icu-date <https://github.com/tarantool/icu-date#readme>
+*   tracing <https://github.com/tarantool/tracing/>
+
+For Tarantool Enterprise modules, see the
+`Tarantool Enterprise documentation <https://www.tarantool.io/en/enterprise_doc/rocksref/>`_.