Improve logging

[vitalybaev]

Backup and sync are now very various and powerful, but logging isn't I guess. We have only json file, email and webhook. But in our work we use great messengers, like Slack (or HipChat, and event Telegram), so I thought about improving it. I know, you don't like third party dependencies, but what about of using Monolog for this purpose? With one dependency we have some of needed handlers and if we would like to wide amount of available loggers in future it could be pretty easy. What do you think?

[sebastianfeldmann]

I'm always struggling with those kind of decisions. Adding Monologs logging power to phpbu seems like a great idea and makes sense.

I'm wondering if it should be included into the main repository or if it should be added as a plugin like phpbu-monolog that you have to install via composer additionally.

We could build a plugin detection so if you install it you don't have to register the plugin manually within a bootstrap file for more convenience.

And we could decide if we would want to integrate it into the phar release by default. Or keep it separate.