fix adding new account in macos

Fix mailsync ping command

Fix mutt-wizard

Fix muttrc for mac

Add files for offlineimap_profile and offlineimap_header

Update README with MacOS install instructions

configuring offlinemap to get emails from Microsoft Exchange via Davmail I run into a problem, which could be fixed by changing "port" to "remoteport" in the remote-part of the config.
See also here:
https://github.com/OfflineIMAP/offlineimap/blob/master/offlineimap.conf
# This option stands in the [Repository RemoteExample] section.
# Specify the port.  If not specified, use a default port.
#remoteport = 993

If running offlineimap it will show the following warning message (tested when using GMAIL)...

 XOAUTH2 authentication failed: AUTHENTICATE command error: BAD ['Client aborted AUTHENTICATE command.
<randomstring>']. Data: DIEF2 AUTHENTICATE XOAUTH

... and then continue with the download/sync of emails.
You can get rid of the warning message, when adding auth_mechanisms = LOGIN .offlineimaprc in the <...>-remote section.

On account change new account's mailboxes are being appended to the old
one's. This commit forces mailboxes list to be cleared before adding new
items to it.

This is first working version of an added login query to the account
creation process. It fixes the first part of #6, but there still needs
to be more testing for the second part of that issue, which concerns
creating accounts with domains not listed in domain.csv.