sysutils/orch: update to v0.2

Highlights:

• Support for other platforms (Linux, macOS, NetBSD, OpenBSD)
• Functionality pushed into lua modules, orch(1) is now a light driver on top of the library. The library's intended to be installed for use by other Lua scripts if desired, and exports env and run_script(scriptfile, cfg).
• More bits imported into the .orch script environment
• stty() support to change some flags on the termios of the child
• Support for Lua 5.2 was dropped

The build system was rewritten in the interim to use cmake instead of
bmake directly, so uidfix and related hacks have now disappeared.

Makefile restructured slightly to appease portlint, and both EXAMPLES
and MANPAGES options added to be able to disable those.