net/freerdp: sort out port

1. Move manpages from LOCALBASE/man/ to LOCALBASE/share/man/.
2. Update ARM NEON support (details are at https://reviews.freebsd.org/D43127).
3. Unification of the pkg-plist with upcoming net/freerdp3: replace "2" with "%%MAJORVERSION%%".

Approved by: arrowd (mentor)
Differential Revision: https://reviews.freebsd.org/D43352

(cherry picked from commit 8d656131d2060996dafb4e8006622dc684a095d6)