Pass reference time / locales of messages to the model

1. It is required to set Person object when constructing a Message object
   now. As it is very important to know whether the message is from
   local user or remote user. Introduced PERSON_USER_REMOTE if
   the caller just want a simple way to specify a remote user.

2. Use detectLanguages to detect the locale of the messages
   If the model finds the detected language is not something
   it supports, model may suppress smart reply.

3. Pass the reference time to the model. So model can resolve
   the absolute time from a relative date string like "tomorrow 6pm".

BUG: 120809869

Test: atest ActionsSuggestionsHelperTest.java
Test: atest ConversationActionsTest.java

Change-Id: Ie079848e9b3d9bb8800f7f95d73e289e831968f8