Add tests coverage for mutating function and standalone MKL

[Crown421]

The CI testing of this package is currently not covering

• mutating functions fun!
• using standalone MKL instead of MKL.jl

[Crown421]

#31 add testing for standalone MKL.
Further, adds scheduled testing on Julia nightly.

[Crown421]

Mutating functions are being tested now, and standalone MKL is no longer necessary.

Done.