[consolidated] support for recognized use-cases

[testbird]

The current defaults do not yet fully work for common use cases.

The required additional config options are explained in the wiki:
https://github.com/deltachat/deltachat-core/wiki/Use-Cases

Implementing this also solves at least the following issues:

• Emails from other MUA are shown in the chat #49
• No alert for new message in Contact Requests #228 first-time messages (contact request) from not yet known contacts can not be seen and answered, because the (...) Email Log is not shown by default.
• [use case: chat app and parallel regular MUA] let chat not disturb regular email clients deltachat-core#60

[r10s]

Thank you very much for your thoughts. Maybe it is also a good idea to use the wiki for such general thoughts (the core wiki then). The issues tend to fade out after some time ...

[testbird]

Good idea, created a wiki page for this issue.

[r10s]

might be targeted by https://github.com/deltachat/deltachat-core/milestone/2

closing this for now here, of course, the discussion can go on in the new support forum at https://support.delta.chat