Enable QV64/128 experiments

[itoko]

Implement techniques proposed in https://arxiv.org/abs/2008.08571

[Avhijit-Nair]

Hi! I would like to work on this issue. Can you provide more context?

[ajavadia]

@Avhijit-codeboy thanks this already has people assigned to it.
The 3 issues linked here are needed for this to work, after which the release can go out.

[levbishop]

Do we need another issue for a PassManager to stitch together the pieces here? Or can that punt to a later release?

[mtreinish]

Do we need another issue for a PassManager to stitch together the pieces here? Or can that punt to a later release?

I think for 0.18 just having the passes is enough, we can document an example pass manager in a tutorial on replicating QV64/QV128 with terra. We can look at adding a pass manager with everything in 0.19 because I think it would be good to do it with #5978