Customize blade directive to allow changing the div id

[RobertBoes]

While reading through #141 and #178 I noticed the $expression that's passed by the blade compiler wasn't treated as a PHP expression, but rather as a string. I think this should be treated as an expression to follow blade standards and this will allow people to conditionally change the id like so @inertia(true ? 'foo' : 'bar').

This means @inertia(foo) is not allowed, since that's not a valid expression. However, all directives mentioned in the blade docs have valid PHP as parameter for the blade directives ('title', count($records) === 1) and for example yield(content) wouldn't work either since that doesn't contain a valid PHP expression.

The easiest solution is to output the expression in the directive directly to pass that to a method call, so the directive would return this '<?php echo app(\MyClass::class)->render('.$expression.'); ?>'. This works as expected, unfortunately Inertia also needs to output the $page variable which is passed as view data. I've tried to come up with a solution for this, but this is far from perfect, since I don't really like the usage of an anonymous class for this. Maybe someone can help me figure out a better solution, or this PR can be used to improve one of the other PR's

Oh and I used @claudiodekker's tests from #141, so I added you as co-author :)

[claudiodekker]

I'll be closing this PR, as we've actually already re-implemented this as part of #339 👍