[fix] brands: add variables from build env to sphinx-doc

We have some variables in the build environment which are also needed in the
sphinx-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>

docs/conf.py

@@ -4,9 +4,9 @@ import  sys, os
 from searx.version import VERSION_STRING
 from pallets_sphinx_themes import ProjectLink
 
-GIT_URL = os.environ.get("GIT_URL", "https://github.com/asciimoo/searx")
-SEARX_URL = os.environ.get("SEARX_URL", "https://searx.me")
-DOCS_URL = os.environ.get("DOCS_URL", "https://asciimoo.github.io/searx/")
+from searx.brand import GIT_URL
+from searx.brand import SEARX_URL
+from searx.brand import DOCS_URL
 
 # Project --------------------------------------------------------------