Add quickselect algorithm. Quickselect is a selection algorithm to find the kth smallest element in an unordered list.

Describe the bug

In the following reproducer, t.Scan() prints values for column out_x.out_x but the output is truncated to out_x.out, which can be quite confusing for larger trees with nested branches:

root [0] TTree t;
root [1] int x = 42;
root [2] t.Branch("out_x", &x)
(TBranch *) 0x5559ed5dc4f0
ro

There are several ValueErrors, NotImplementedErrors, etc, across the codebase.

We should create a mechanism to get clean, and uniform error messages.