use `exec` to turn httpd into parent process. This is important for docker signalling such as `docker stop ${container_id}`
add `set -e` which stops the entrypoint script if any command exits with a non-zero exit code.
Reviewed-on: #6
Co-authored-by: throwaway <developerthrowaway@protonmail.com>
Co-committed-by: throwaway <developerthrowaway@protonmail.com>