Revert "Do not generate an cookie as root when loading"

This reverts commit fed4519b3fa90f92cef1a4f9802eabc9692508c1.
Don't chop last character when logging to journald

Messages never ends with a new line character so there's no point
in chopping the last character.

This fixes log messages missing the last character and closes #185.
Change authDir into stateDir
Set the auth file name to be the display name only
Change the user and group of the auth file to the sddm user when possible
Don't create .Xauthority for the sddm user
Merge pull request #180 from AnAkIn1/authfilefix

Fix cookie generation and set the correct cookie path for the greeter
Use standard installation paths

CMake already has support for standard installation paths
including GNUInstallDirs.  Remove our definitions and use theirs.

While we are here, use a more conventional path for data files.
Merge pull request #189 from plfiorini/cmakeinstalldirs

Use standard installation paths
Fix configuration file path

Use absolute path for the configuration file otherwise sddm won't
find it.
Set default paths for SYSCONFDIR and LOCALSTATEDIR

GNUInstallDirs defines relative paths, when asked for absolute paths
like we do here it just prepends CMAKE_INSTALL_PREFIX resulting in paths
like /usr/etc and /usr/var for SYSCONFDIR and LOCALSTATEDIR
respectively.

However this is far from what we want, plus I find it unconvinient
to ask packagers and developers to pass arguments for those path
every time when we know the vast majority of people want /etc and
/var.
Use GNU installation directories for more files

There were a few places where we were still using semi-hardcoded
paths.
Fix man pages installation

MAN1_OUTPUT and MAN5_OUTPUT are meant to be lists so they shouldn't be
quoted.
Fix sddm daemon path in systemd unit
Merge pull request #190 from plfiorini/fixcmake

Fix CMake paths problems
Check chown return value

Print an error and quit when we cannot chown the socket.
Merge pull request #193 from ilpianista/master

Check chown return value
Add QAuth library and helper

Currently SDDM provides only a simple username/password authentication.
More exciting credential requests such as password change are not supported.

PAM also requires double forking to work better and that's not currently
implemented.

Importing QAuth here opens a lot of possibilities.

More changes to SDDM are required to handle more complicated credential
requests, for now we just want to start using QAuth to gain the same
features as current SDDM. We will improve as we move forward.

More details: https://github.com/sddm/sddm/wiki/Authentication
Use QAuth for authentication

Now that SDDM includes QAuth we can take advantage of its improved
authentication support.

This is based on PR #155 by Martin Bříza <mbriza@redhat.com>
Improve greeter stderr and stdout logging from daemon

Unquote output and avoid extra spaces.