Callback parameter when checking or fixing the tree

[G3z]

I've added an optional callback to fixTree() countErrors() and relative methods so a user can configure the query

My main use case i to disable global scopes (I've added tests for this use case)

usage

Category::fixTree(function($query){
  $query->withoutGlobalScopes([AnUnwantedScope::class]);
});

Category::isBroken(function($query){
  $query->withoutGlobalScopes([AnUnwantedScope::class]);
});

[jonnott]

@lazychaser It would be great if you could merge one of these PRs (there are a few similar), basically so global scopes are removed (or can be removed) when calling isBroken() or fixTree().

Often global scopes are used for tenanting or other purposes, but when checking or fixing the tree, we want to treat the entire table as one whole, and fix lft and rgt values across all entries in the table.

Having an optional query scope passed in, as in this PR, seems like a good approach, as then there's no breaking change to the current default behaviour of the methods.