Allow to skip AESM service install

My goal is to build a Docker image where the following libraries get installed during the build: libsgx_urts.so, libsgx_enclave_common.so, libsgx_dcap_ql.so.

This is prevented by the following checks:
https://github.com/intel/linux-sgx/blob/734513886f83caff1d7e93263ba4c946fa5aa927/linux/installer/common/libsgx-enclave-common/install.sh#L95-L99

https://github.com/intel/linux-sgx/blob/734513886f83caff1d7e93263ba4c946fa5aa927/linux/installer/common/psw/install.sh#L96-L100

Docker does not have systemctl/initctl, and in fact I do not want to run aesm as a service inside the Docker container. Forwarding /dev/sgx and /var/run/aesmd/aesm.socket from the host when launching (not building!) the container should be enough (right?) .

During the Docker build, I cannot use the published Debian packages because of this. Therefore, I need to build from source and also patch the files above by removing the `exit 5` statement so that the build continues.

It would be great if Docker images are supported as an official install destination. Turning hard exits into warnings would be a good start. Ideally, separating packages more, so that it's possible to install just the runtime libraries without aesm would be even better.