Show non-deltachat emails by default for new installations

[iequidoo]

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[iequidoo]

Since it caused the massive discussion with many people involved, i expect at least 3 approvals here :)

[gerryfrancis]

@iequidoo If only I could code, I would review this PR, of course! ;) However, thanks for your invitation!

[r10s]

lgtm technically, thanks a lot! i also reviewed the changed tests wrt changed default - i first thought we do not have a test for classic-mail not showing up when show_emails==0, however, there is test_adhoc_group_show_chats_only(), so that seems good enough.

and i agree, let's wait a bit longer wrt merging and get more approvals. there were some ideas around wrt a (device) message once the first classic email is received or so. just saying as it was discussed before, i am not sure this is needed, it may be even more confusing. as also discussed, in a mixed setup the more annoying part seems the other way round, dc messages shown in classic mua.

all in all, i think the new default is less confusing and we can give it a try - the old one was mainly because of some classic email types not being supported, which has changed since then.

[iequidoo]

there were some ideas around wrt a (device) message once the first classic email is received or so. just saying as it was discussed before, i am not sure this is needed, it may be even more confusing

I decided not to add a device message because maybe it's better just to point to that in "What's new in X?" message and what a user should do to switch to the new defaults. A separate message may be excessive

[Hocuri]

🎉