Add notice that the sandbox is currently unavailable. (#731)

Signed-off-by: Jeroen Laverman <jeroen.laverman@bosch-si.com>

README.md

@@ -27,7 +27,7 @@ Next to the hawkBit core hosted here the project maintains as well [examples](ht
 
 We offer a sandbox installation that is free for everyone to try out hawkBit. However, keep in mind that the sandbox database will be reset from time to time. It is also not possible to upload any artifacts into the sandbox. But you can use it to try out the Management UI, Management API and DDI API. Keep in mind as well that you are not permitted to store any kind of personal data in the sandbox.
 
-https://hawkbit-demo-sandbox.eu-gb.mybluemix.net/UI/
+_NOTE: The sandbox is currently unavailable. We will be back soon!_ 
 
 In addition the following vendors offer free trial accounts for their hawkBit compatible products:
 

docs/content/gettingstarted.md

@@ -6,11 +6,10 @@ weight: 20
 ## On Sandbox
 
 We offer a sandbox installation that is free for everyone to try out hawkBit's [Management UI](/hawkbit/ui/), 
-[Management API](/hawkbit/apis/management_api/), and [Direct Device Integration API](/hawkbit/apis/ddi_api/):  
-**[<i class="fas fa-desktop">&nbsp;</i> https://hawkbit-demo-sandbox.eu-gb.mybluemix.net/UI/](https://hawkbit-demo-sandbox.eu-gb.mybluemix.net/UI/)**
+[Management API](/hawkbit/apis/management_api/), and [Direct Device Integration API](/hawkbit/apis/ddi_api/).
 
 {{% warning %}}
-The sandbox database will be reset from time to time. It is also not possible to upload any artifacts into the sandbox. Moreover, you are not permitted to store any kind of personal data in the sandbox.
+The hawkBit sandbox is currently unavailable. [More infos ...](/hawkbit/sandbox/sandboxunavailable/)
 {{% /warning %}}
 
 In addition, the following vendors offer free trial accounts for their Eclipse hawkBit compatible products:

docs/content/sandbox/sandboxunavailable.md

@@ -0,0 +1,11 @@
+---
+title: Sandbox
+weight: -201
+---
+
+## We are sorry, but the sandbox is currently unavailable
+
+{{% warning %}}
+We are migrating the hawkBit Sandbox to be hosted by the Eclipse Foundation. Therefore, it is currently unavailable. 
+We will be back soon. 
+{{% /warning %}}

docs/layouts/partials/drawer.html

@@ -21,7 +21,7 @@
       {{ if (eq (trim .Site.Params.provider " " | lower) "github") | and (isset .Site.Params "repo_url") }}
         <ul class="repo">
           <li class="repo-download">
-            <a href="https://hawkbit-demo-sandbox.eu-gb.mybluemix.net/UI/login/#/" target="_blank" title="hawkBit Sandbox" data-action="sandbox">
+            <a href="/hawkbit/sandbox/sandboxunavailable/" target="_blank" title="hawkBit Sandbox" data-action="sandbox">
               <i class="fas fa-desktop"></i> &nbsp; Sandbox
             </a>
           </li>