Changes sgx-psw to append `aesm` to `LD_LIBRARY_PATH`:
- Append instead of prepend to allow for overriding in service config
- As we already add a wrapper to add `aesm` to `LD_LIBRARY_PATH` it is
not necessary to also set in `LD_LIBRARY_PATH` of the systemd service.
Co-authored-by: Vincent Haupert <mail@vincent-haupert.de>