`project!` and `projectrand!` probably do not make sense here

[Krastanov]

These two functions are declared here but used only in QuantumClifford (where historically they come from).

In principle, they can have general API, but the QuantumClifford implementation does not conform to a nice general API.

One of the two needs to happen:

1. a very breaking release to QuantumClifford so that it can have project! and projectrand! which follow an API that would make sense for QuantumOptics and others
2. removing project! and projectrand! from here and leaving them only in QuantumClifford

Choices here need to also be kept consistent with project_traceout! which is used a bit more.