Add a link to the project architecture overview

[alexkarezin]

Adding a link to the high-level project documentation. Provides list of modules, libraries, module dependency diagram and other high-level information intended to simplify new developer's introduction to the project.

[alexkarezin]

@geosk , any chance you can take a look at this? The documentation page is here. I hope it will be useful for all new DeviceHive contributors.

[alexkarezin]

@geosk , any chance you can take a look at this? The documentation page is here. I hope it will be useful for all new DeviceHive contributors.

@geosk or @phariseo or @illia-sernikov can anybody take a look please? Thanks!

[bhcuong2008]

Could u show me where or what component interacts/processes directly with Kafka Broker. I'd like to know topic, its structure, but can not find it.
Thanks.