Make getContents public to be able to use Twig templates for other things then web pages (i.e. mail templates)

Not all properties are of string type in metadata, so we need to
remove this so we can use the function for any type of language
keyed metadata item.

updated twig to version 3 and added wrapper for translation via symfony/twig-bridge

Co-authored-by: Ulrik nielsen <un@ipwsystems.dk>

Reimplement getPreferredTranslation outside of IdPDisco so it's reusable
and much more complete. The new method will search the current, default
and fallback language for a displayable string in various metadata
fields. This should be much more complete and robust than previous
approches. Make it a Twig filter so it can also be used there.

This commit consists of patches automatically generated for this project on https://scrutinizer-ci.com

Only transitive dependency remains now.

* Migrate email utils to non-static

* Migrate http utils to non-static

* Migrate net utils to non-static

* Migrate random utils to non-static

* Migrate system utils to non-static

* Migrate time utils to non-static

* Migrate xml utils to non-static

* Upgrade notes

* Update test-framework

* Fix tests

Previously, would show inappropriate precision, like "0.0598134 hours ago"
or "1490532.4129 hours from now" depending on the expiration date.

Convert to our wrapper class for assertions

* Remove deprecated classes

* Remove support for certificate fingerprints

* Remove many deprecated methods and pieces of code

* Remove SAML1.1/Shib1.3 support

* Remove many superfluous annotations

* Update unit test to work with new PHPunit

Closes #1268 
Closes #1020 
Closes #431 
Closes #167 
Closes #151 

* Migrate assertions to Webmozart

* Use strict variables in Twig, except for our TemplateTest; throw exception on missing variables

* Fix issues due to Twig strict_variables=true

* Fix for #1229

* Fix metadata-template

* Added Kernel class to handle request

* Kernel handle request

Kernel is loaded in SimpleSAML\Module class
Removed Router and ControllerResolver classes

* Added route command (squash)

* Use symfony application and cache

* Updated to today's standards

* Fix for Symfony4 & Catch environment from ENV variable

* Standardize location of routes/services files

* Trying to make slashes work properly in all situations

* Convert XML to YML

* Fix some template-names and endpoints

* Rename Controller-classes

* Update dependencies

* Fix routing files

* TooManyArguments

* Fix TypeCoercion

* PSR-12

* Fix rebase mistake

* Rebase lock-file

* Fix Psalm

* Add strict_types declaration

Co-authored-by: Sergio Gómez <decano@gmail.com>