feat(ui): add ability to inject some css or javascript files

close #1009

client/public/index.html

@@ -7,6 +7,7 @@
     <link rel="manifest" href="%PUBLIC_URL%/manifest.json"/>
     <meta name="viewport" content="width=device-width, initial-scale=1"/>
     <meta name="theme-color" content="#33b5e5"/>
+    <meta name="html-head" content="replace">
 
     <!--
       The AKHQ_PREFIX_PATH placeholder magic value is replaced during serving by server

docs/docs/configuration/akhq.md

@@ -34,4 +34,24 @@ These parameters are the default values used in the topic creation page.
 ### Topic Data
 * `akhq.ui-options.topic-data.sort`: default sort order (OLDEST, NEWEST) (default: OLDEST)
 
-
+### Inject some css or javascript
+* `akhq.html-head`: Append some head tags on the webserver application
+Mostly useful in order to inject some css or javascript to customize the web application.
+
+Examples, add a red banner on production environment :
+```yaml
+kestra:
+  webserver:
+    html-head: |
+      <style type="text/css">
+        .logo-wrapper:after {
+          display: block;
+          content: "Local";
+          position: relative;
+          text-transform: uppercase;
+          text-align: center;
+          color: white;
+          margin-top: 10px;
+        }
+      </style>
+```

src/main/java/org/akhq/controllers/StaticFilter.java

@@ -27,6 +27,10 @@ public class StaticFilter implements HttpServerFilter {
     @Value("${micronaut.server.context-path}")
     protected String basePath;
 
+    @Nullable
+    @Value("${akhq.html-head}")
+    protected String htmlHead;
+
     @Override
     public Publisher<MutableHttpResponse<?>> doFilter(HttpRequest<?> request, ServerFilterChain chain) {
         return Publishers
@@ -66,9 +70,9 @@ public Publisher<MutableHttpResponse<?>> doFilter(HttpRequest<?> request, Server
     }
 
     private String replace(String line) {
-
         line = line.replace("./ui", (basePath == null ? "" : basePath) + "/ui");
 
+        line = line.replace("<meta name=\"html-head\" content=\"replace\">", this.htmlHead == null ? "" : this.htmlHead);
 
         return line;
     }