TYPO3 Core

Currently, both ext_conf_template and TypoScript constants are using the same syntax - however, for the ext_conf_template the relevant parser parts were duplicated and adjusted. Now we have the situation that there are two parsers for the same thing as well as a lot of code duplication. To be able to replace the constants/ext_conf_template (and in the future: site settings) with another syntax, the duplication should be removed and a central parser used for all use cases.