x11-servers/xwayland: Sync options with xwayland-devel

• Provide the option to compile with libdecor for client-side decoration and enable it by default.
• Provide the option to compile with libei for emulated input and enable it by default.
• Enable xdmcp
• Enable xcsecurity needed for X11 forwarding.
• Use some meson default (dri3, ipv6, glamor, sha1 and xkb_dir)
• Remove unneeded USES egl

Differential Revision: https://reviews.freebsd.org/D44644
Reviewed by: bapt, jbeich
Sponsored by: Beckhoff Automation GmbH & Co. KG