security/libprelude: Take MAINTAINER'ship, STAGE & Modernize

• Take Maintainership
• Enable STAGE support
• Tweak MASTER_SITES https -> http (portlint)
• Add LICENSE and LICENSE_FILE
• Deprecate USE_AUTOTOOLS for libtool (-> USES)
• Sort USES and OPTIONS
• Use OPTIONS helpers as much as possible for now [1]
• Add --enable-static to CONFIGURE_ARGS to retain the static lib
• Assign and Use ETCDIR rather than hardcoding
• Use the install-strip install target
• Update pkg-plist, use @sample and other goodies

While I'm here, bump dependent ports since our SHLIB major version has
changed

[1] https://reviews.freebsd.org/D665

Approved by: portmgr (implicit, bump unstaged port)