Remove SpycYAMLParser

[PKuhlmay]

It seems that the SpycYAMLParser is only used in one line:

extension_builder/Classes/Configuration/ExtensionBuilderConfigurationManager.php

Line 145 in 78ecb67

return SpycYAMLParser::YAMLLoadString(file_get_contents($settingsFile));

We have to consider if we can remove the whole SpycYAMLParser.php file and adjust this line of code to use the TYPO3YamlFileLoader from TYPO3 or from Symfony.

This results into less code to maintain.

Also the tests needs to be adjusted then.

[PKuhlmay]

https://symfony.com/doc/current/components/yaml.html#reading-yaml-files