✨(helm) allow to load custom theme file in a configMap

In order to load a custom theme file with our helm chart, we allow to
load the content of a file into a config map and then use this configmap
as a volume in the backend deployment

Dockerfile

@@ -87,10 +87,6 @@ RUN wget https://svn.apache.org/repos/asf/httpd/httpd/trunk/docs/conf/mime.types
 # Copy entrypoint
 COPY ./docker/files/usr/local/bin/entrypoint /usr/local/bin/entrypoint
 
-# Copy configuration
-VOLUME [ "/configuration" ]
-COPY ./configuration /configuration
-
 # Give the "root" group the same permissions as the "root" user on /etc/passwd
 # to allow a user belonging to the root group to add new users; typically the
 # docker user (see entrypoint).