SDP Guide Updates:
* Removed Section 6.5 (Database Modifications); that content not useful in the Upgrades section.
* Added new section 'The Offline Database'.
* Added FAQ on converting from cleartext to encrypted passwords.
* Clarified that live_checkpoint.sh can be used on commit and edge servers.
* Enhanced detail for what various scripts do.
* Refactored so 'Scripts for Maintenance of offline_db' is in a better place.
* A few typo corrections.