Add checks for removed classes

Like in #33 (closed) for functions / methods, we also have to check usage of deprecated classes:

• https://docs.typo3.org/typo3cms/extensions/core/7.6/Changelog/7.0/Breaking-61782-DeprecatedDocumentTemplateClassesRemoved.html
• https://docs.typo3.org/typo3cms/extensions/core/7.6/Changelog/7.0/Breaking-57396-ExtbaseDeprecatedPropertyMapperRemoved.html also see https://review.typo3.org/#/c/28915/7/typo3/sysext/core/Migrations/Code/LegacyClassesForIde.php and https://review.typo3.org/#/c/28915/7/typo3/sysext/fluid/Migrations/Code/ClassAliasMap.php
• https://docs.typo3.org/typo3cms/extensions/core/7.6/Changelog/7.0/Breaking-57382-FlashMessageApi.html also see https://review.typo3.org/#/c/28912/7/typo3/sysext/extbase/Migrations/Code/ClassAliasMap.php
• https://docs.typo3.org/typo3cms/extensions/core/7.6/Changelog/7.0/Breaking-61786-ExtbaseDeprecatedTypeHandlingServiceRemoved.html
• https://docs.typo3.org/typo3cms/extensions/core/7.6/Changelog/7.0/Breaking-62673-ExtbaseDeprecatedCodeRemoved.html#removed-php-classes
• https://docs.typo3.org/typo3cms/extensions/core/7.6/Changelog/7.0/Breaking-62670-DeprecatedCodeRemovalInMultipleSysexts.html#removed-php-classes
• https://docs.typo3.org/typo3cms/extensions/core/7.6/Changelog/7.0/Breaking-62416-DeprecatedCodeRemovalInCoreSysext.html#removed-php-classes
• https://docs.typo3.org/typo3cms/extensions/core/7.6/Changelog/7.3/Breaking-67229-FormEngineRelatedClasses.html
• https://docs.typo3.org/typo3cms/extensions/core/7.6/Changelog/7.3/Breaking-66669-BackendLoginControllerRefactored.html
• https://docs.typo3.org/typo3cms/extensions/core/7.6/Changelog/7.3/Breaking-66429-RemoveIdentityMapFromPersistence.html
• https://docs.typo3.org/typo3cms/extensions/core/7.6/Changelog/7.3/Breaking-63846-FormEngineRefactoring.html
• https://docs.typo3.org/typo3cms/extensions/core/7.6/Changelog/7.4/Breaking-67811-RteApi.html
• https://docs.typo3.org/typo3cms/extensions/core/7.6/Changelog/7.4/Breaking-68243-MoveNotUsedFrontendDocumentTemplate.html
• https://docs.typo3.org/typo3cms/extensions/core/7.6/Changelog/7.5/Breaking-69568-FormEngine.html
• https://docs.typo3.org/typo3cms/extensions/core/7.6/Changelog/7.5/Breaking-68401-SqlParserMovedIntoEXTdbal.html
• https://docs.typo3.org/typo3cms/extensions/core/7.6/Changelog/7.5/Breaking-63000-MigrateCshmanualToExtbase.html
• https://docs.typo3.org/typo3cms/extensions/core/7.6/Changelog/7.6/Breaking-66369-RemovedElementBrowserRelatedClasses.html
• https://docs.typo3.org/typo3cms/extensions/core/7.6/Changelog/7.6/Breaking-45899-SplitClassImportExportIntoClassesImportAndExport.html