[FEATURE] Show forgot password only if conf showForgotPassword = 1

Do not show forgot password form in felogin, if the forgot
password link for the login form has been disabled.

Resolves: #50138
Resolves: #34597
Releases: 6.2
Change-Id: I40b490cb09dc339067ff4ff0bc0d0afe0464a456
Reviewed-on: https://review.typo3.org/22541
Reviewed-by: Markus Klein
Tested-by: Markus Klein
Reviewed-by: Marco Huber
Tested-by: Marco Huber
Reviewed-by: Georg Ringer
Tested-by: Georg Ringer