Change systemd definition to log to file rather than syslog

[the-moog]

As per issue #20

[the-moog]

I think the changes are correct but I don't yet have a test environment to prove it.

[ma1uta]

Thanks for PR, but I don't think that it's a great idea. May be some one want write logs to the syslog. Also you don't need to specify the -v option because starting from 2.3.0 version you can configure log level in the configuration.

[the-moog]

I would disagee. Syslog for the the system not one service on the system. Spamming syslog with messages from every service masks issues that affect the system as a whole. Synapse uses it's own logfile. IMO let the users decide it's not my system or yours so each will have their own requirements. Add a logfile option which can be one of STDOUT or file or STDERR or pipe, etc.

[bpcurse]

It's a good idea to let the user decide where to write the log. Default however should be syslog.

[ma1uta]

Ok, I see you. I can offer the next solution: current behavior remains without changes but I'll add the configuration option to configure logger, it may be STDOUT, file or remote networt port. Additionally admins can configure the logger to be asynchonous for example.