(maint) Remove module metadata

Since we're not releasing strings as a moudle anymore, remove the
module metadata.

metadata.json

@@ -1,30 +0,0 @@
-{
-  "name": "puppetlabs-strings",
-  "version": "0.4.0",
-  "author": "Puppet Labs",
-  "summary": "Puppet documentation via YARD",
-  "license": "Apache-2.0",
-  "source": "https://github.com/puppetlabs/puppetlabs-strings",
-  "project_page": "https://github.com/puppetlabs/puppetlabs-strings",
-  "issues_url": "https://tickets.puppetlabs.com/browse/PDOC",
-  "dependencies": [
-  
-  ],
-  "tags": [
-    "yard",
-    "yardoc",
-    "puppet",
-    "dev",
-    "docs",
-    "documentation"
-  ],
-  "operatingsystem_support": [
-  
-  ],
-  "requirements": [
-    {
-      "name": "puppet",
-      "version_requirement": ">= 3.7.0 < 5.0.0"
-    }
-  ]
-}