ui: add RUCIO_HTTPD_ADDITIONAL_REDIRECTS environment variable

This variable can be used to add an additional `Redirect` in the apache config. The value should be a string with the format `/{path} {url}`.

For example `RUCIO_HTTPD_ADDITIONAL_REDIRECTS="/foo http://bar"` will add the following lines to the apache config located at `/etc/httpd/conf.d/rucio.conf` inside the container:

```bash
    Redirect /foo http://bar
```

You can add multiple refirects if you specify the value of the environment variable in the following format: `/{path1} {url1}, /{path2} {url2}, ...`. For example `RUCIO_HTTPD_ADDITIONAL_REDIRECTS="/foo http://bar, /baz http://qux"` will add the following lines to the apache config located at `/etc/httpd/conf.d/rucio.conf` inside the container:

```bash
    Redirect /foo http://bar
    Redirect /baz http://qux
```

ui/README.md

@@ -100,6 +100,21 @@ This variable can be used to add an additional `ProxyPass` and corresponding `Pr
     ProxyPassReverse /foo http://bar
 ```
 
+### `RUCIO_HTTPD_ADDITIONAL_REDIRECTS`
+
+This variable can be used to add an additional `Redirect` in the apache config. The value should be a string with the format `/{path} {url}`. For example `RUCIO_HTTPD_ADDITIONAL_REDIRECTS="/foo http://bar"` will add the following lines to the apache config located at `/etc/httpd/conf.d/rucio.conf` inside the container:
+
+```bash
+    Redirect /foo http://bar
+```
+
+You can add multiple refirects if you specify the value of the environment variable in the following format: `/{path1} {url1}, /{path2} {url2}, ...`. For example `RUCIO_HTTPD_ADDITIONAL_REDIRECTS="/foo http://bar, /baz http://qux"` will add the following lines to the apache config located at `/etc/httpd/conf.d/rucio.conf` inside the container:
+
+```bash
+    Redirect /foo http://bar
+    Redirect /baz http://qux
+```
+
 ### `RUCIO_HTTPD_PROXY_PROTOCOL_ENABLED`
 
 This variable can be used to enable the `ProxyProtocol` module in the apache config. The default is `Off`. It sets the `RemoteIPProxyProtocol` directive in the apache config.

ui/rucio.conf.j2

@@ -82,6 +82,12 @@ CacheRoot /tmp
  ProxyPass {{ RUCIO_HTTPD_ADDITIONAL_PROXY_CONF}}
  ProxyPassReverse {{ RUCIO_HTTPD_ADDITIONAL_PROXY_CONF }}
 {% endif %}
+{% if RUCIO_HTTPD_ADDITIONAL_REDIRECTS is defined %}
+{% for redirect in RUCIO_HTTPD_ADDITIONAL_REDIRECTS.split(',') %}
+ Redirect {{ redirect|trim }}
+{% endfor %}
+ ProxyPassReverse {{ RUCIO_HTTPD_ADDITIONAL_PROXY_CONF }}
+{% endif %}
 {% if RUCIO_HTTPD_PROXY_PROTOCOL_ENABLED | default('False') == 'True' %}
  RemoteIPProxyProtocol On
  RemoteIPProxyProtocolExceptions 127.0.0.1 ::1 {{ RUCIO_HTTPD_PROXY_PROTOCOL_EXCEPTIONS | default('') }}