split the mail config file based on Transport

[arhimede]

mail.local.php.dist in frontend, admin and api

also the global file https://github.com/dotkernel/dot-mail/blob/4.0/mail.global.php.dist

split in 2 separate dist files:

1. master: define the Transport and the message options
2. a smtp dist file with specific to smtp option , IF any

[arhimede]

also remove the FIle and Memory options, are not used

[arhimede]

linked to the issue #320