LP#1410369: Schema and supporting IDL entries

LP#1410369: Schema and supporting IDL entries

This commit adds the table actor.usr_message,
a trigger to populate actor.usr_message as rows
get adding to actor.usr_note (or get updated to make
non-public notes become public), and new columns in
action.event_definition for specifying how to generate
user messages from A/T events.

It also copies over existing public user notes as
new, "read" user messages, as the current display
of the old user notes will be removed from TPac.

Signed-off-by: Mike Rylander <mrylander@gmail.com>
Signed-off-by: Galen Charlton <gmc@esilibrary.com>