Separate different helpers in `UClassHelpers` into their own units

[delphidabbler]

Per TODO comment at:

codesnip/Src/UClassHelpers.pas

Line 14 in 02656b8

{ TODO: Separate different helpers into their own units, within a ClassHelpers

There are different unrelated helpers all with UClassHelpers.

Separate them into their own units, within a ClassHelpers scope. E.g. ClassHelpers.Controls, ClassHelper.Graphics.

[delphidabbler]

Given that record helpers are also possible, a better scope name than ClassHelpers could be just Helpers.