Debug/Info output causes issues

[amulet1]

We need to redesign logging as there are multiple cases when an output of a particular command that calls the plugin is captured/analyzed. Injected debug or info messages there cause issues/errors.

For example, qm showcmd <vmid> is one example of such command. It output a kvm command line with parameters for a VM, but if the debug is enabled, there will be multiple Debug :: ... lines prepended. There are many other cases like that.

A possible solution is to use syslog for any plugin output.

[timansky]

I'm agree that syslog can be more informative, but ui log are also important.
Idea was to understand which log are necessary.
For user choice atleast log level need to be implemented. Info|warn|error|(debug for syslog| debug for ui)