Smooth TYPO3 migrations using TYPO3 scanner

TYPO3 keeps track of breaking changes and deprecations in RST documents since version 7. Based on these documents, we can make la list of 'matchers'. With the help of a PHP parser, which converts every PHP file to an Abstract Syntax Tree (AST), every file is checked. A report (in any desired format) shows which lines of code need to be modified. This tool makes the code (already in the install tool of TYPO3 v9) available as a standalone commandline tool. This can be used for migrating TYPO3 websites from version 6.2 (and up).