Bump version to 0.2.0
logind: Merge PropertiesChanged handlers
libseat: Expand logging in all backends
libseat: Only print backend attempts for matches
terminal: Explain FreeBSD current_vt behavior
terminal: Construct TTY paths correctly on FreeBSD

FreeBSD TTY paths are contructed in the kernel using the %r formatter,
which in this case ends up being a base 32 encoding.

The base 32 implementation is taken more or less directly from wlroots
commit fc6c0ca12e94.
terminal: FreeBSD VT num is 1 higher than tty num

This was causing all VT and TTY changes to be applied to the wrong TTY.
terminal: Set K_RAW and term raw mode on FreeBSD

Taken from X11, weston and consolekit2 ports for FreeBSD.

Setting just K_CODE as done before makes input seemingly have no ill
effects, but it is still buffered and possibly send to the terminal
after application exit if stdin is never drained. Setting raw mode
appears to be needed to solve that issue.

A K_OFF-like VT keyboard setting like Linux has would seem more
appropriate, but that is not currently available to us on FreeBSD.
simpletest: Set log level to debug
Introduce libseat_set_log_level

The default level is SILENT. log_init no longer takes an initial log
level (so that calls to libseat_set_log_level prior to log_init work

This will be replaced with a libseat API to set the log level.
Introduce libseat_set_log_handler

This allows libseat users to register a custom logging function.
Rename enum log_level to libseat_log_level

This is preparatory work for exposing a public function to set libseat's
log handler.
libseat: Remove useless logind fallbacks

The logind code is based on the wlroots implementation, which in turn
contained copy-paste code from Mutter that serves no purpose here.
logind: Set session type from env
logind: Remove session type check
logind: Remove useless check
meson: Set license to MIT
seatd: Use path-based chmod/chown

The fd variants do not seem to work for sockets
ci: Install scdoc for alpine and archlinux
man: Add simple seatd(1) page