Replace LESS processing package

As I was going to replace `components/font-awesome` with the official `fortawesome/font-awesome` package to update to FA 6, I came across the following:

```php
ParseError: Unexpected input in _sizing.less on line 15, column 5
13|
14| // step-based scale (with alignment)
15| each(.fa-sizes(), {
16| .@{fa-css-prefix}-@{key} {
17| .fa-size(@value);
18| }
```

The `wikimedia/less.php` package had its last release on Dec 2020. There are issues open for updating to Less.js 3/4 and closed ones that refer to that regarding this issue with `each` (https://github.com/wikimedia/less.php/issues/49).

It does not look like they are actively maintaining it (just closing PRs, as they stated in some comment) so we may have to replace the package with another.