dm crypt: update URLs to new cryptsetup project page

Cryptsetup home page moved to GitLab.
Also remove link to abandonded Truecrypt page.

Signed-off-by: Milan Broz <gmazyland@gmail.com>
Signed-off-by: Mike Snitzer <snitzer@redhat.com>
(cherry picked from commit e44f23b32dc7916b2bc12817e2f723fefa21ba41)
Signed-off-by: Alex Shi <alex.shi@linaro.org>