[feature suggestion] transfer mail between account

[zafriryak]

In the app I can move mail only in the same account between folders.
I thought to add a feature for moving mail between different accounts.

So my question is what are you thinking about it
if it possible because i didn't saw it in any android mail app and it is exists in outlook and ios
if you think i can make it what do you suggest me to study first for making this feature.

Thanks in advance zafrir.

[cketti]

Same as #760