Create Toxics at startup

[cbgbt]

Is your feature request related to a problem? Please describe.
It's slightly inconvenient to configure toxics after-the-fact with the client when proxies can be configured using a config file.

Describe the solution you'd like
This would be a clear departure from toxiproxy, but I wonder if it would make sense to allow creation of toxics via configuration as well.

Describe alternatives you've considered
None. The status quo works well.

[cbgbt]

I think this is also possible if I switch to using core for my use-case, so I have yet another work around. I'll leave the issue open in case you have any interest in discussing expanding ProxyConfig (or some other solution) for this.

[oguzbilgener]

Yeah, I also found it inconvenient to have to re-configure the toxics every time the server starts up.

Originally I left this project at feature parity, but I'm not against new useful features like this :)

[oguzbilgener]

The config file could be JSON, YAML or anything else that we could provide quick support with using a library.