Add custom_js site param for enabling custom js (#182)

* Add custom_js site param for enabling custom js 

I've hit that when adding Cookie Consent on my web page. https://github.com/insites/cookieconsent

* PR Remarks - added Custom JS into exampleSite

* Update layouts/_default/baseof.html

Co-Authored-By: Luiz F. A. de Prá <luizdepra@users.noreply.github.com>

* Update CONTRIBUTORS.md

CONTRIBUTORS.md

@@ -37,3 +37,4 @@
 - [D_DAndrew](https://d-dandrew.github.io)
 - [Wataru Mizukami](https://github.com/tarumzu)
 - [Yudi Widiyanto](https://github.com/yudiwdynto)
+- [Łukasz Mróz](https://github.com/mrozlukasz)

exampleSite/config.toml

@@ -42,6 +42,9 @@ disqusShortname = "yourdiscussshortname"
     # Custom CSS
     custom_css = []
     
+    # Custom JS
+    custom_js = []
+
 [taxonomies]
   category = "categories"
   series = "series"

layouts/_default/baseof.html

@@ -60,7 +60,11 @@
     {{ end }}
 
     {{ range .Site.Params.custom_css }}
-      <link rel="stylesheet" href="{{ . | relURL }}">
+      <link rel="stylesheet" href="{{ . | relURL }}" />
+    {{ end }}
+
+    {{ range .Site.Params.custom_js }}
+      <script src="{{ . | relURL }}"></script>
     {{ end }}
     
     <link rel="icon" type="image/png" href="{{ .Site.Params.favicon_32 | default "/images/favicon-32x32.png" | absURL }}" sizes="32x32">