chore: remove unused docker entrypoint script

docker/entrypoint.sh

@@ -1,15 +0,0 @@
-#!/usr/bin/env sh
-set -e
-
-if [ -n "$PUID" ] && [ "$PUID" -ne 0 ] && \
-   [ -n "$PGID" ] && [ "$PGID" -ne 0 ] ; then
-  echo "info: creating the new user vikunja with $PUID:$PGID"
-  groupmod -g "$PGID" -o vikunja
-  usermod -u "$PUID" -o vikunja
-  chown -R vikunja:vikunja ./files/
-  chown vikunja:vikunja .
-  exec su vikunja -c /app/vikunja/vikunja "$@"
-else
-  echo "info: creation of non-root user is skipped"
-  exec /app/vikunja/vikunja "$@"
-fi