opium package: add version 4.1 and update blas/lapack dependencies (#25591)
opium package: add version 4.1 and update blas/lapack dependencies (#25591)

- remove unneeded dependency on blas
- create external-lapack variant
- patch makefile to not build lapack if `+external-lapack`

Also: 

- fix homepage link
- set parallel = False
- make references to `spec` consistent
- remove unneeded `build` method
LLNL/spack,LLNL/spack,LLNL/spack,LLNL/spack,LLNL/spack