Introduce UOW endpoint

[yentsun]

Details:

• https://venture-api.fandom.com/wiki/UOW
• https://venture-api.fandom.com/wiki/Worker

Probably needs a Redis-based throttle storage. Worker posts UOW, storage creates a TTL record wich locks the worker until it expires.

• get workers ID, perform lookup
• create throttle record based on worker's capacity
• issue an event on UOW reducing appropriate jobs completion time
• return next possible UOW time in response