When the user add searx as a search engine, the browser loads the /opensearch.xml URL without the cookies.
Without the query parameters, the user preferences are ignored (method and autocomplete).
In addition, opensearch.xml is modified to support automatic updates,
see https://developer.mozilla.org/en-US/docs/Web/OpenSearch
We have some variables in the build environment which are also needed in the
templating process. Theses variables are relavant if one creates a fork with
its own branding. We treat these variables under the term 'brands'.
Signed-off-by: Markus Heiser <markus.heiser@darmarit.de>
