libraries-and-tools: rename to integrations

I want to create a more consistent naming system across the repos. Some
of our projects won't have libraries or tools (like Clair) but others
have integrated their software with Clair in various ways.

So, use a generic term: integrations.

README.md

@@ -106,7 +106,7 @@ Now it's time to dig into the full etcd API and other guides.
 - Explore the full gRPC [API][api].
 - Set up a [multi-machine cluster][clustering].
 - Learn the [config format, env variables and flags][configuration].
-- Find [language bindings and tools][libraries-and-tools].
+- Find [language bindings and tools][integrations].
 - Use TLS to [secure an etcd cluster][security].
 - [Tune etcd][tuning].
 
@@ -114,7 +114,7 @@ Now it's time to dig into the full etcd API and other guides.
 [api]: ./Documentation/dev-guide/api_reference_v3.md
 [clustering]: ./Documentation/op-guide/clustering.md
 [configuration]: ./Documentation/op-guide/configuration.md
-[libraries-and-tools]: ./Documentation/libraries-and-tools.md
+[integrations]: ./Documentation/integrations.md
 [security]: ./Documentation/op-guide/security.md
 [tuning]: ./Documentation/tuning.md