[FEATURE] Add a rel="nofollow" on the "Forgot your password" link

There is no reason for search engines to crawl the "Forgot your
password?" page. Add a rel="nofollow" in the felogin to advice
search engines not to crawl the page.

Change-Id: I98f9dd4ffd385bc273437200feeefc09317bfd6b
Resolves: #22025
Releases: 4.7
Reviewed-on: http://review.typo3.org/6889
Reviewed-by: Georg Ringer
Reviewed-by: Mario Rimann
Reviewed-by: Simon Schaufelberger
Tested-by: Simon Schaufelberger
Reviewed-by: Steffen Ritter
Tested-by: Steffen Ritter

typo3/sysext/felogin/ext_typoscript_setup.txt

@@ -17,6 +17,7 @@ plugin.tx_felogin_pi1 {
 		#parameter and additionalParams are set by extension
 	linkConfig {
 		target = 
+		ATagParams = rel="nofollow"
 	}
 	
 		#preserve GET vars - define "all" or commaseperated list of GET-vars that should be included by link generation