add !lastnews command and BREAKING-NEWS TAG to provide last 5 important news on private

[gcanosa]

This feature would allow recently joined users to the channel, to receive the last 5 or 10 news in private to avoid flooding and repeating on the configured channel.

[gcanosa]

Also add BREAKING-NEWS flag into Configuration file, that will allow to specify a feed as BREAKING-NEWS, therefore the bot will show those messages in RED-BOLD to highlight them as important, and !lastnes command will only show BREAKING NEWS/relevant news on private.

[gpoppino]

Maybe we could split this issue into two issues:

1. Show breaking news in red-bold.
2. Implement !last to show N number of breaking news in a private message to the user.