docs: image gallery viewer (#905)

* add assets, photoswipe html element to body

* add single script, gallery for multiple items

* update docs for image gallery

* fix relative links

* inject image script on mount

* replace inline script

* remove facebook, twitter, pinterest sharing

* fix hover on share

* fix start img aspect radio, reduce size

* right align json script

* right align go script

* change script background

site/docs/start/00-quick-start.en.md

@@ -14,7 +14,14 @@ You can either use [ZITADEL.ch](https://zitadel.ch) or deploy a dedicated **ZITA
 To register your free [organisation](administrate#Organisations), visit this link [register organisation](https://accounts.zitadel.ch/register/org).
 After accepting the TOS and filling out all the required fields you will receive a email with further instructions.
 
-<img src="img/accounts_org_register.png" alt="Organisation Register" width="1000px" height="auto">
+<div class="zitadel-gallery" itemscope itemtype="http://schema.org/ImageGallery">
+    <figure itemprop="associatedMedia" itemscope itemtype="http://schema.org/ImageObject">
+        <a href="img/accounts_org_register.png" itemprop="contentUrl" data-size="1472x1000">
+            <img src="img/accounts_org_register.png" itemprop="thumbnail" alt="Organisation Overview" />
+        </a>
+        <figcaption itemprop="caption description">Organisation Register</figcaption>
+    </figure>
+</div>
 
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