refactor: split out Netlify module

Creates dedicated module for Netlify deployment:

github.com/wowchemy/wowchemy-hugo-themes/modules/wowchemy-plugin-netlify

See #2754

modules/wowchemy-plugin-netlify/README.md

@@ -0,0 +1,21 @@
+# Wowchemy Plugin for Netlify
+
+A build plugin to integrate your Hugo site seamlessly with Netlify.
+
+The plugin automatically generates a `_headers` and `_redirects` file at the root of the public folder to configure [HTTP headers](https://www.netlify.com/docs/headers-and-basic-auth/) and [redirects](https://www.netlify.com/docs/redirects/) on Netlify.
+
+By default, the plugin will help secure your site with some common security headers. You can easily add or replace headers through the plugin config.
+
+## Install
+
+1. Edit `config/_default/config.yaml` to install the `wowchemy-plugin-netlify` module:
+
+   ```yaml
+   module:
+     imports:
+       - path: github.com/wowchemy/wowchemy-hugo-themes/modules/wowchemy-plugin-netlify
+   ```
+
+## Configure
+
+- 📚 [View the **documentation**](https://wowchemy.com/docs/hugo-tutorials/security/)

modules/wowchemy-plugin-netlify/config.yaml

@@ -0,0 +1,19 @@
+module:
+  mounts:
+    - source: src/layouts
+      target: layouts
+mediaTypes:
+  text/netlify:
+    delimiter: ''
+    suffixes: ['']
+outputFormats:
+  headers:
+    baseName: _headers
+    isPlainText: true
+    mediatype: text/netlify
+    notAlternative: true
+  redirects:
+    baseName: _redirects
+    isPlainText: true
+    mediatype: text/netlify
+    notAlternative: true

modules/wowchemy-plugin-netlify/go.mod

@@ -0,0 +1,3 @@
+module github.com/wowchemy/wowchemy-hugo-themes/modules/wowchemy-plugin-netlify
+
+go 1.15

modules/wowchemy/config.yaml

@@ -16,21 +16,6 @@ markup:
   tableOfContents:
     startLevel: 2
     endLevel: 3
-mediaTypes:
-  text/netlify:
-    delimiter: ''
-    suffixes: ['']
-outputFormats:
-  headers:
-    baseName: _headers
-    isPlainText: true
-    mediatype: text/netlify
-    notAlternative: true
-  redirects:
-    baseName: _redirects
-    isPlainText: true
-    mediatype: text/netlify
-    notAlternative: true
 sitemap:
   changefreq: weekly
 module: