MFH: r514482 r514629
www/firefox: update to 70.0
Changes: https://www.mozilla.org/firefox/70.0/releasenotes/
PR: 240440
Security: e1c901e9-ed1e-415d-8272-f171bfc265bd
Approved by: ports-secteam blanket
Differential Revision: https://reviews.freebsd.org/D21572