scripted-diff: ci: Rework docker naming

DOCKER in names is confusingly used as synonym for "image", "container",
and "ci". Fix the confusion by picking the term that fits the context.

-BEGIN VERIFY SCRIPT-
 ren() { sed -i "s:$1:$2:g" $( git grep -l "$1" ) ; }

 ren DOCKER_PACKAGES CI_BASE_PACKAGES
 # This better reflects that they are the common base for all CI
 # containers.

 ren DOCKER_ID CI_CONTAINER_ID
 # This is according to the documentation of "--detach , -d: Run
 # container in background and print container ID".

 ren DOCKER_NAME_TAG CI_IMAGE_NAME_TAG
 # This avoids confusing with CONTAINER_NAME and clarifies that it is an
 # image.

 ren DOCKER_ADMIN CI_CONTAINER_CAP
 # This clarifies that it is a capability added to the container.

 ren DOCKER_CI_CMD_PREFIX CI_EXEC_CMD_PREFIX
 # This brings it in line with the CI_EXEC naming.

-END VERIFY SCRIPT-

ci/test/05_before_script.sh

@@ -38,7 +38,7 @@ if [ -n "$ANDROID_HOME" ] && [ ! -d "$ANDROID_HOME" ]; then
 fi
 
 if [ -z "$NO_DEPENDS" ]; then
-  if [[ $DOCKER_NAME_TAG == *centos* ]]; then
+  if [[ $CI_IMAGE_NAME_TAG == *centos* ]]; then
     # CentOS has problems building the depends if the config shell is not explicitly set
     # (i.e. for libevent a Makefile with an empty SHELL variable is generated, leading to
     #  an error as the first command is executed)