[8.x] Add runway query scope

[duncanmcclean]

This pull request implements a runway query scope, which allows developers to customise the queries executed by Runway.

For example: maybe you want to disable global scopes, or only return models created in the past year.

class YourModel extends Model
{
	public function scopeRunway($query)
	{
		return $query->where('something', true);
	}
}

Under the hood, all queries will now go through the Resource::newEloquentQuery() method.

Related: #669

[github-actions]

Released as part of v8.3.0.