Ability to change the from address

Is your feature request related to a problem? Please describe.

No response

Describe the solution you'd like

The ability to change the from address to whatever I want, and for the app to use the recipient by default when replying to an email

Describe alternatives you've considered

No response

Additional context

I'm using a different address (.myname@mydomain.tld) for every service, and in most email clients I'm able to edit the from address to send emails from whatever I want, as long as the smtp server accepts it of course.
It's also very handy if when hitting 'reply' the from is pre-filled with the recipient from the email I'm replying to, since that would almost always be one of these addresses.

Hopefully this is trivial, since it's just changing the from: header.
In SnappyMail it's just a textbox which is ideal, in RoundCube it's very annoying since you have to add an identity for each but it's an option. Thunderbird has all the bells and whistles with the ability to customize it to whatever and auto pre-filling it based on regexp, which is great but probably overkill.

Start by tracing the compose and reply flows described in the issue, including how the app passes the From header to the SMTP server. Done means users can choose a permitted From address and replies default to the original recipient, with the behavior working when the SMTP server accepts the address.