Add Youtube search provider.

searchproviders.yml

@@ -10,6 +10,24 @@
     #title: title
     #link: uri
     
+- name: Youtube
+  abbr: YT
+  type: WebScraperSearcher
+  search_url: https://www.googleapis.com/youtube/v3/search?part=snippet&type=video
+  search_fields:
+    query: q
+    secret: key
+  search_headers:
+    #Authorisation: Bearer $SECRET
+    Accept: application/json
+  format: json
+  result_selector: /items
+  result_fields:
+    title: /snippet/title
+    artist: /snippet/channelTitle
+    link: /id/videoId
+  link_format: https://youtube.com/watch?v=$LINK
+    
 - name: Soundcloud
   abbr: SC
   type: WebScraperSearcher