Merge branch 'rename_license_template_api' into 'master'

Rename Licenses API to License Templates API

## What does this MR do?

Earlier I renamed this in EE, thinking license templates was an EE-only feature. This backports that change to CE. Thanks to @vsizov for pointing out this error.

See https://gitlab.com/gitlab-org/gitlab-ee/merge_requests/400 for the EE merge request. 

See merge request !4957

lib/api/api.rb

@@ -39,7 +39,7 @@ module API
     mount ::API::Issues
     mount ::API::Keys
     mount ::API::Labels
-    mount ::API::Licenses
+    mount ::API::LicenseTemplates
     mount ::API::MergeRequests
     mount ::API::Milestones
     mount ::API::Namespaces

lib/api/license_templates.rb

@@ -1,6 +1,6 @@
 module API
-  # Licenses API
-  class Licenses < Grape::API
+  # License Templates API
+  class LicenseTemplates < Grape::API
     PROJECT_TEMPLATE_REGEX =
       /[\<\{\[]
         (project|description|

spec/requests/api/license_templates_spec.rb

@@ -1,6 +1,6 @@
 require 'spec_helper'
 
-describe API::Licenses, api: true  do
+describe API::API, api: true  do
   include ApiHelpers
 
   describe 'Entity' do