syslog-ng via TLS connections

How to test?

vagrant up
ssh to demo server
```
vagrant ssh
```
generate CA for both client and server
```
cd /vagrant
make setup-syslog-ng-key
```
start syslog-ng server
```
cd /vagrant
make run-syslog-ng
```
received log from client would be persisted in /tmp/log/syslog
open up another terminal and ssh to demo server as step.2
quick test syslog-ng server with loggen to make sure syslog-ng is ready to serve
```
cd /vagrant
make run-loggen-tcp-client
```
test syslog-ng server with golang
```
cd /vagrant
make run-syslog-go-client
```

References