[fix] container: setup minimal (#6268)

Start minimal, use defaults, and extend later on. The templates are no longer
checked for changes, which was confusing and annoying after a while.

See: https://github.com/searxng/searxng/issues/6261#issuecomment-4716008282

.dockerignore

@@ -1,5 +1,6 @@
 *
 
+!container/*.template.*
 !container/entrypoint.sh
 !searx/**
 !requirements*.txt