[TASK] Escape reserved characters in yaml files

In preparation to update the symfony/yaml dependency to v4,
proper escaping needs to take place.
Following
http://symfony.com/doc/current/components/yaml/yaml_format.html#strings
unsufficient escaping will result in a parse error.

Change-Id: Ic6eb3c2825c8c877d292aaa21e4b0e1a9fee6fe4
Resolves: #84420
Releases: master
Reviewed-on: https://review.typo3.org/56292


Reviewed-by: Christian Kuhn <lolli@schwarzbu.ch>
Tested-by: Christian Kuhn <lolli@schwarzbu.ch>
Tested-by: TYPO3com <no-reply@typo3.com>
Reviewed-by: Jan Helke <typo3@helke.de>
Tested-by: Jan Helke <typo3@helke.de>