Add more granular features in font-locking

Add more granular features in font-locking

There is now support for three font-locking levels, 'minimal',
'moderate' and 'full'.  The richest experience is to be expected from
the 'full', and all levels are enabled by default.

* lisp/progmodes/js.el (js--treesit-font-lock-settings): New defvar
renamed from 'js--treesit-settings'.

(js--treesit-font-lock-settings): New defvar renamed from
'js--json-treesit-settings'.

* lisp/progmodes/ts-mode.el (ts-mode--font-lock-settings): New defvar
renamed from 'ts-mode--settings'.