Template refactor rebased

Fix the calls to the old getTranslation() and getAttributeTranslation() methods from SimpleSAML_XHTML_Template.

Restore the rest of the public methods in SimpleSAML_XHTML_Template that were removed, make them wrappers of the new methods, and mark them as deprecated.

Restore SimpleSAML_XHTML_Template::getLanguageCookie() and setLanguageCookie() temporarily, as wrappers over the new methods in SimpleSAML\Locale\Language.

More bugfixes. includeLanguageFile() has been moved from SimpleSAML_XHTML_Template to SimpleSAML\Locale\Translate.

More bugfixes. The SimpleSAML\Locale\Language::$languageParameterName and SimpleSAML\Locale\Language::$language properties should be private, and therefore not accessed from the outside of their respective classes. Add getters instead.

Add a method SimpleSAML_XHTML_Template::getTranslator() to retrieve the SimpleSAML\Locale\Translate instance local to the template, and use it to fix a bug in a template of the consent module.

Bugfix. The consentAdmin module was still calling SimpleSAML_XHTML_Template::getTag(), while that method has been moved to \SimpleSAML\Locale\Translate.

Rename \SimpleSAML\Locale\Translate::t_not_translated() to the more concise (and camel caps) getStringNotTranslated().

Return lang_merge() to SimpleSAML_XHTML_Template, as it was public, and mark it as deprecated. Use array_merge_recursive() instead.

Rename \SimpleSAML\Locale\Translate::getTranslation() to the more comprehensive \SimpleSAML\Locale\Translate::getPreferredTranslation().

add OIDs from SIS (Swedish Standards Institute), TK 450 AG04

Try to make it build with the saml module included by using the phpunit version we are requiring instead of the one preinstalled.

Include .editorconfig file