log: Add -timestamp option

Allows users to define a new timestamp as formatted by strftime through CUtils::FormatTime
Additionally -sanitize is no longer necessarily the first argument, but -timestamp and the actual timestamp must be last as it can contain spaces.
Prioritize reconnecting znc admins.
Import external module: privmsg
Import external module: privmsg_prefix
Modified for YourBNC
Update README.
Update README.md
Update README.md
Update README.md