[#59323898] Basic rsyslog

Manage rsyslog and reproduce default Ubuntu configurations. With the
exceptions of:

- UFW no longer gets a separate log. I don't care enough to a) fork this
  file, b) risk not purging old configs.
- Catch all logging is slightly different.
[#59323898] cdn_logs module for redirector

Configures rsyslog with a TCP input which logs to a single file. It presents
an SSL certificate to allow others to verify who the server is, but not to
verify who the clients are. Firewall does not restrict specific addresses -
that's done by the VSE.
[#59323898] cdn_logs log rotation.
[#59323898] Enable cdn_logs on transition-logs

And include a self-signed cert/key for use in Vagrant. The real cert/key
will be committed to hiera in gds/ci-deployment.
Merge pull request #101 from alphagov/59323898-cdn_logs

[#59323898] CDN logs for transition