net-p2p/transmission: Update 3.00 -> 4.0.4 & modernize port

This turns previous slave-ports net-p2p/transmission-{cli,daemon,gtk,qt,utils}
and www/transmission-web into flavours of net-p2p/transmission.

What's new in 4.0.4 (vis-a-vis 3.00)

• Resource Efficiency: code profiled and improved
• Code Modernization: standardization on C++ tools
• Support for BitTorrent v2 torrents & hybrid torrents
• New web client
• Lots of bug fixes

Changelog: https://github.com/transmission/transmission/releases/tag/4.0.4

PR: 269504
Reported by: dutchman01@quicknet.nl
Approved by: rigoletto, tcberner (maintainer timeout)
Reviewed By: fcharlier_ploup.net
Differential Revision: https://reviews.freebsd.org/D40910