Issue #1272 - SSP refuses to use temp dir if it doesn't own it, even though it can write to it (#1314)

* Issue #1272 - SSP refuses to use temp dir if it doesn't own it, even though it can write to it
This has been addressed using the is_writable function instead of checking for UID, which only works in a Linux environment

Co-authored-by: Aaron St. Clair <astclair@ecrs.com>

* 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 

* 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

This reverts commit 6bcea51e.

Stream wrappers were assumed to be relative paths. When using a stream wrapper (e.g. s3://) it was appended to the given base path.