tinymail service refactor

[trydofor]

more details about send/post/emit/auto

• send return bool or throw
• post return long

[trydofor]

Save and Sync single send. and return,

• false, if check fail.
• throw if send fail, MailRetryException if async retry.
• true, otherwise.

Save and Sync single send, fire and forget, no exception throw. and return,

• -2, if throw non MailRetryException.
• -1, if check fail.
• 0, if send success.
• >now(), (estimated retry time) if fail and async retry

Async batch send, no exception throw. auto in batch send. and return,

• -2, if throw non MailRetryException.
• -1 if check fail.
• >now() estimated retry time if fail and async retry