Add links to docs and API in the footer

BTCPayServer/Views/Shared/_Footer.cshtml

@@ -1,4 +1,4 @@
-@using BTCPayServer.Abstractions.Extensions
+@using BTCPayServer.Abstractions.Extensions
 @inject BTCPayServer.Services.BTCPayServerEnvironment _env
 
 <footer class="btcpay-footer">
@@ -24,6 +24,14 @@
                 <vc:icon symbol="donate"/>
                 <span style="margin-left:.4rem">Donate</span>
             </a>
+            <a asp-controller="UIHome" asp-action="SwaggerDocs" class="d-flex align-items-center" target="_blank">
+                <vc:icon symbol="api"/>
+                <span style="margin-left:.4rem">API</span>
+            </a>
+            <a href="https://docs.btcpayserver.org/" class="d-flex align-items-center" target="_blank" rel="noreferrer noopener">
+                <vc:icon symbol="docs"/>
+                <span style="margin-left:.4rem">Docs</span>
+            </a>
             @if (!string.IsNullOrEmpty(_env.OnionUrl) && !Context.Request.IsOnion())
             {
                 <a href="@_env.OnionUrl" class="d-flex align-items-center" target="_onion" rel="noreferrer noopener" role="button" data-clipboard="@_env.OnionUrl" data-clipboard-confirm-element="CopyTorUrlText" style="min-width:9em;">