Detect system MKL without pkg-config

[termoshtt]

Resolve #37 , #40

• [x] Create ubuntu and centos container using apt/yum install, and confirm pkg-config is broken
  • https://hub.docker.com/repository/docker/rustmath/mkl-ubuntu
  • https://hub.docker.com/repository/docker/rustmath/mkl-centos
• [x] Seek test for ubuntu/centos container
• [x] Detect MKL without pkg-config
  • Seek /opt/intel/mkl or ${MKLROOT} directory