Deltachat-android: mailto:-links without address should work as "share"

[r10s]

while mailto-links with e-mail addresses work line a charme since https://github.com/deltachat/deltachat-android/issues/473, mailto:-links without e-mail addresses (sth. as mailto:?subject=bla&body=blub, used eg. on golem.de) currently do not work as expected.

these links open the contact list; once a contact is selected, however, the proposed text is gone.

i think these links should work in the same way as sharing: offering the chatlist and adding the text as draft. the user can click "send" or modify the text before sending then.

[angelo-fuchs]

Testlink for easier testing.

[Boehrsi]

Will have a look :).

[r10s]

great :)

[Boehrsi]

Should be fixed by https://github.com/deltachat/deltachat-android/pull/724

[r10s]

should be fixed by https://github.com/deltachat/deltachat-android/pull/724