Include `@tturbo` as loop vectorisation possibility for the CPU backend

[luraess]

Something to consider as alternative or supplement to the current Threads.@threads option. The @tturbo macro allows for threaded aux instruction exposed by the LoopVectorization package. See here https://github.com/luraess/parallel-gpu-workshop-JuliaCon21#parallel-cpu-implementation for an example. There may be some restrictions on handling if conditions inside the loop.

[omlins]

reopened as foreseen GPU optimizations should also make the usage of LoopVectorization feasible without or little approach divergence between CPU and GPU code generation