fix: Slowdown/Warmup/DB Marshaling

[ochaton]

• First, reaction time of the kharon was too low: it awaited 15s before start to poll. When kharon drained the lymbo, it went to sleep for 15s. Now, new mechanics of slowdown was introduced, so kharon will go to sleep gradually.
• Polling has been smoothen out. Now, kharon is aware about minimal-reaction-time and respects it to poll tickets from lymbo. Now it CANNOT poll tickets faster!
• User's defined data now is marshalled to json.RawMessage.
• Also optional tubes were added to separate tickets between different instances of Kharon. All tickets by default move into "default" tube