Support more breakpoints

[axos88]

Is it possible to change the number of breakpoints? 4 is not too many, and different projects have different needs.

Bootstrap supports a dynamic number of breakpoints for example, that would be awesome!

[agertenbach]

+1 -- Also looking for the correct way to handle this in the latest versions of Primeflex -- the previously documented SCSS variables appear to have changed and we need to enable progressive support for larger breakpoints

[axos88]

This works for me currently, but some proper documentation would be nice:

@import 'primeflex/core/variables';

$xxl: 1600px;
$fhd: 1920px;
$qhd: 2560px;

$breakpoints: (
  'sm': $sm,
  'md': $md,
  'lg': $lg,
  'xl': $xl,
  'xxl': $xxl,
  'fhd': $fhd,
  'qhd': $qhd
);

@import 'primeflex/primeflex.scss';