Video how-to links for Jira and Zendesk connectors (#519)

Author: Paul-Cornell

snippets/general-shared-text/jira.mdx

@@ -1,3 +1,14 @@
+<iframe
+width="560"
+height="315"
+src="https://www.youtube.com/embed/JR5mcukOSUQ"
+title="YouTube video player"
+frameborder="0"
+allow="accelerometer; autoplay; clipboard-write; encrypted-media; gyroscope; picture-in-picture"
+allowfullscreen
+></iframe>
+
+
 - A [Jira Cloud account](https://www.atlassian.com/try/cloud/signup?bundle=jira-software&edition=free) or 
     [Jira Data Center installation](https://confluence.atlassian.com/adminjiraserver/installing-jira-data-center-938846870.html).
 - The site URL for your [Jira Data Center installation](https://confluence.atlassian.com/jirakb/find-your-site-url-to-set-up-the-jira-data-center-and-server-mobile-app-954244798.html) or Jira Cloud account. 

snippets/general-shared-text/zendesk.mdx

@@ -1,3 +1,13 @@
+<iframe
+width="560"
+height="315"
+src="https://www.youtube.com/embed/f2yeXwSvZtE"
+title="YouTube video player"
+frameborder="0"
+allow="accelerometer; autoplay; clipboard-write; encrypted-media; gyroscope; picture-in-picture"
+allowfullscreen
+></iframe>
+
 - A [Zendesk account](https://www.zendesk.com/register/).
 - Your [Zendesk subdomain](https://support.zendesk.com/hc/en-us/articles/4409381383578-Where-can-I-find-my-Zendesk-subdomain).
 - The login email address for your Zendesk account.