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

* Raise minimum PHP version to 7.0

* Remove tests pre-PHP 7.2

* Upgrade dev dependencies

* Ignore tests for deprecated class

* Add typehints; not touching public API

* Remove none-array replacements-param; old behaviour from pre-1.4 release

* Psalm fixes

* Add upgrade notes

* PSR-12

We don't control we type of the default value

PSR-12 compliancy

* Ensure getConfig* functions can only return Configuration

* Cleanup after #1189

* Deprecate Configuration::getConfigList

Fixes for the remainder of lib/SimpleSAML

With a dynamic configuration, it is not desirable to load from literal files
By storing a configuration object against a filepath, subsequent calls to
getConfig work transparently, bypassing the disk load step.

Fixes https://github.com/simplesamlphp/simplesamlphp/issues/818