Make text-scale-mode optionally adjust the header line

Make text-scale-mode optionally adjust the header line

* lisp/face-remap.el
(text-scale-remap-header-line-face): New buffer local variable.
(text-scale-mode): Adjust header line if above variable is non-nil.
(face-remap--clear-remappings, face-remap--remap-face): New defuns.
* lisp/face-remap.el: Arrange to watch text-scale-mode-remapping.
(text-scale--refresh): New function.

* lisp/emacs-lisp/tabulated-list.el (tabulated-list-mode): Use
text-scale-remap-header-line.  (Bug#41852)