Lazy (delayed) Quick Sort with all storage pre-allocated

Objectives

• No extra allocation (except when built with meticulous checks).
• Leveraging standard Rust (alloc::vec::Vec, alloc::collections::VecDeque...)
• Minimal & guard-controlled unsafe code and core::mem::MaybeUninit.

Initial Limitations

Both of the following limitations will be lifted later:

• Stack depth (recursive).
• Needs alloc.