MFH: r482197 r482402

www/firefox: update to 63.0

Changes: https://www.mozilla.org/firefox/63.0/releasenotes/
PR: 229893
Security: 7c3a02b9-3273-4426-a0ba-f90fad2ff72e
Approved by: ports-secteam (miwi)
Differential Revision: https://reviews.freebsd.org/D16356