v1.3.0 - Handling Large Datasets

This release handles large databases and the timeout errors that come from handling thousands of entries all at the same time.

We assume that anyone using the Eloquent Driver for Statamic has the potential to be managing large amounts of data, and the current implementation of the sitemap addon doesn't deal with that very well. This release refactors code and also takes into consideration handling large database queries, whilst mitigating N+1 issues that may arise from looping Statamic's Entries facade.

Big shout out to @bagwaa for popping this together!