Dont load site at startup to log site version

Move the logging of the site version into Bot() to prevent
site access issues occurring before main() or Bot() have
requested a Site() object.

Bot now log the site version of each site that is fetched via
the Bot.site property

Bot.__init__ sets self.generator if it is in kwargs.

Bot.run updates Bot.site if Bot.site was not set prior to run()
being invoked.

Remove the run() method from delete.py, so it uses the new
treat()-only system where Bot.run() manages the site property.

Bug: 69895
Change-Id: If8a71b78b639288c7cf4329b1292c88d889ce1fa
Merge "Dont load site at startup to log site version"