Various patches

[askibinski]

            "Error on clean install - service needs config entity purl_provider before it is available": "patches/purl/purl-d8-install-purl.patch",
            "Error on install - PDOException for key length with InnoDB (updated for github d8 version), reset static cache": "patches/purl/purl-d8-install-innodb.patch",
            "Code consistency/bug fixes": "patches/purl/purl-d8-consistency-fixes.patch",
            "Do not cache url without routes": "patches/purl/purl-d8-do_not_cache_empty_routes.patch",
            "Fix compatibility with Drupal core Internal Page Cache and Redirect": "patches/purl/purl-d8-page-cache-redirect-compatibility-1.patch",
            "Fix compatibility with Drupal 8.5.": "patches/purl/purl-d8-drupal-8.5-compatibility.patch"

Note: there is still an url-generator-host-option.patch in the root of the module, but is that still useful? Doesn't seem to be applied.