Add Files Support

Resolve extra issues with most recent 4.x version

Fix, error when entity generation tries to get file entity

Please create a merge request so the review/merging process is smoother.

Sorry, I'll sooner, first I need to reach a fully version of patch 100% funcional and tested

Just adding a new verification. In case that the field "link_count" exists, the hook update 8305 will not be runned again, since this hook is beeing called on hook 8407 and in some cases this made the update fail.

Removed the truncate() from the code on #48, this way will not be necessary run the sitemap build after the hook execution

Reroll of the excellent work in #49 for the 4.1.7 branch:

Reroll of the excellent work in #49 for the 4.1.7 branch, this time without bugs!!!

Thank you for working on this however it is not working.
In patch 40 there was added section to support "overrides_entity_type" to be array however in 43 and after that was removed. As a result of that removal the isOverwrittenForEntityType for file is always false because the check $plugin['settings']['overrides_entity_type'] === $entity_type_name will always fail. I will provide updated patch soon.

The #51 works great but it has some unnecessary files like .idea/php.xml, .idea/workspace.xml, .idea/vcs.xml, this new patch removes them making it easier to review.

Ha! Sorry about that. Thanks for the cleanup of me file-piddle there, murilohp.

The patch from #53 had a slight issue that ended up redeclaring function simple_sitemap_update_8408() so I ended up changing the second as function simple_sitemap_update_8409().
Other than that everything else remains the same to #53