[Documentation] Document sync workflow

[danimo]

We should document the basic commands flowing in a typical client session so other people can verify and understand what's happening. This should include:

• Commands sent during setup / start
• Commands sent when a remote server poll is triggered
• Basic Commandfow of a sync, including possible commands
• Commands sent under special conditions

We also need to document special conditions, like extra headers, timing of certain jobs as implemented in the client currently, etc.

Let's do it in a GitHub wiki page

@dragotin @ogoffart @guruz

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[danimo]

https://github.com/owncloud/mirall/wiki/Client-Communication-and-Workflows

[guruz]

@ogoffart Wasn't this done?

[settermjd]

@ogoffart @guruz is this still required?

[guruz]

Let's close this as we have https://github.com/cernbox/smashbox/tree/master/protocol and the code should be the main documentation for engineers.