Core/maps: Change several types to BIGINT to stop overflows in havoc.

Signed-off-by: Martin Stone <martin@d7415.co.uk>
merlin.cfg: Add a note about sharing to Scans.

Signed-off-by: Martin Stone <martin@d7415.co.uk>
(cherry picked from commit 967f3103b20c8ced17b3f13d6ad1fb95717c7c18)
merlin.cfg: Add arthururls section.
Arthur/settings.py: Use new arthururls section.

Signed-off-by: Martin Stone <martin@d7415.co.uk>
(cherry picked from commit c5448a4b59180fa7b8cd031b52b8ef21e9b718bc)
merlin.cfg: Add all alturls (commented out) to default config.

Signed-off-by: Martin Stone <martin@d7415.co.uk>
(cherry picked from commit bc79b31fa5128455d1aa3d9194fd84439098c776)