Refactor authentication config form tests and fix auth backend validation

refs #6011
fixes #5712
Drop obsolete CreateResourceForm class

refs #6011
Rename EditResourceForm to ResourceForm

refs #6011
Refactor ResourceForm tests

refs #6011
Remove form tests that cover only graphical tests

refs #6011
Add test for Zend_View_Helper_DateFormat

refs #6011
Move session tests to correct sub-folder

refs #6011
Add test for Icinga\Util\Translator

refs #6011
Add test for Icinga\Util\String

refs #6011
Move non-factory functions from DateTimeFactory to Icinga\Util\Format
Make DateTimeFactory expecting a string instead of a DateTimeZone
Add test for Icinga\Util\DateTimeFactory

refs #6011
Add test for Icinga\User

refs #6011
Add test for Icinga\User\Preferences

refs #6011
Add test for Icinga\User\Preferences\Store\DbStore

refs #6011
Add test for Icinga\User\Preferences\Store\IniStore

refs #6011
Refactor test for Icinga\Test\BaseTestCase

refs #6011
Add test for Icinga/Logger/Writer/StreamWriter

refs #6011
Remove empty file library/Icinga/File/Csv/Query.php
Rewrite test for Icinga\Config\PreservingIniWriter

refs #6011