Determine if the PHP syncer can and should be the default file copier

Ok. I added build tests that use rsync. All the tests pass. I checked the permissions of the folders and they seem the same.

We will have to figure out if there are still problems with php copier.

Definitely have to figure out if Problem copying git idx files is still a problem

🐛 Failure marker file should be excluded using a relative path Closed: duplicate actually was problem were we should have been using the relative path.

added the related github issues to the summary.

I think we

Test this out locally and this is not actually returning an instance of `PhpFileSyncerInterface` from \Drupal\package_manager\FileSyncerFactory::create even when it hits return $this->phpFileSyncer;

This is not a bug as we require the rsync file syncer and we don't know of any bugs with that.

The answer to this question is "no".

The PHP file syncer is going away from Composer Stager, in favor of using rsync by default in all situations.