[BUGFIX] Remove styles.content.links.target

Remove styles.content.links.target from constants.txt and
lib.parseFunc.ts.

styles.content.links.target has as description in constants.txt pointing
the value is used for frames.

Since fluid_styled_content is focussing on HTML5, this value does not
make sense at all, since frames have been removed from the
specification.
styles.content.links.target should be removed from constants.txt in
fluid_styled_content including the use of this constant value in
lib.parseFunc.ts, the only place where it is used. The typolink
viewhelper does not take this into account also.

Resolves: #77830
Related: #36216
Releases: master
Change-Id: I16e8dc3f77595fde20d8c43d6ab16eb7d590e34b
Reviewed-on: https://review.typo3.org/49839


Reviewed-by: Frank Naegler <frank.naegler@typo3.org>
Tested-by: Frank Naegler <frank.naegler@typo3.org>
Tested-by: TYPO3com <no-reply@typo3.com>
Reviewed-by: Benni Mack <benni@typo3.org>
Tested-by: Benni Mack <benni@typo3.org>