DArray: Tile QR, UndefInitializer, and parallel trapezoidal wrappers

[fda-tome]

This PR concerns the implementation of parallel Triangular and Trapezoidal wrappers. A parallel Tile QR implementation, and undefined initializers for DArrays. This gives ways for "zero-memory" allocation of trapezoidal and triangular DArrays in the future, let's us use Triangular and Trapezoidal wrappers without synchronization, creates undefined memory DArrays in parallel with respect to chunks, and gives way for an easy-to-use QR implementation. All methods follow patterns paved by LinearAlgebra.jl