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

PSR-12 compliancy

* Allow list of entity ids to be loaded to better support idpList

Certain metadata sources, like mdq, were don't support loading all metadata which
prevented them from being used with idplist. This change adds support for allowing
metadata sources to load a list of entities, allowing MDQ to be used for idp list.

Support both hint.cidr and DiscoHints->IPHint

Now using DiscoHints->IPHint to support specified SAML extension for IdP discovery

Minor format and exception message fixes, plus add information about the different communication channels we have today.

Move SimpleSAML_Metadata_MetaDataStorageHandlerMDX to SimpleSAML\Metadata\Sources\MDQ, and stop referring to it as MDX elsewhere.

Rename Utils\HTTP::getSelfHostWithoutPort() to Utils\HTTP::getSelfHostWithNonStandardPort(), change the logic, and reimplement Utils\HTTP::getSelfHost() to depend on use the former. Complete the tests to include the case of port 443 while using HTTPS.

Move SimpleSAML_Utilities::getSelfHost() to SimpleSAML\Utils\HTTP::getSelfHost() and deprecate the former.

Add unit test for it.