TASK: Configure removed or changed signals

Relates: #45

src/Standards/Typo3Update/Configuration/Removed/Signals/7.3.yaml

+# Breaking changes in 7.3: https://docs.typo3.org/typo3cms/extensions/core/7.6/Changelog/7.3/Index.html#breaking-changes
+'7.3':
+  \TYPO3\CMS\Lang\Service\UpdateTranslationService::postProcessMirrorUrl:
+    replacement: 'Change the slot to use the \TYPO3\CMS\Lang\Service\TranslationService::postProcessMirrorUrl signal'
+    docsUrl: https://docs.typo3.org/typo3cms/extensions/core/7.6/Changelog/7.3/Breaking-62983-PostProcessMirrorUrlSignalHasMoved.html

src/Standards/Typo3Update/Configuration/Removed/Signals/7.4.yaml

+# Breaking changes in 7.4: https://docs.typo3.org/typo3cms/extensions/core/7.6/Changelog/7.4/Index.html#breaking-changes
+'7.4':
+  \TYPO3\CMS\Core\Resource\ResourceStorage::preFileAdd
+    replacement: 'The signal will now receive an empty string in $sourceFilePath'
+    docsUrl: https://docs.typo3.org/typo3cms/extensions/core/7.6/Changelog/7.4/Breaking-67545-PreFileAddSignalBehaviourChanged.html