Upgrade Guide - 2.3-RELEASE

[cmb]

Please read the following before asking questions about upgrades.
http://doc.pfsense.org/index.php/UpgradeGuide

[ivor]

Please read the following before starting a thread:

https://doc.pfsense.org/index.php/2.3_Removed_Packages

https://doc.pfsense.org/index.php/2.3_New_Features_and_Changes

https://forum.pfsense.org/index.php?topic=109690.0

https://forum.pfsense.org/index.php?topic=109772.0

https://forum.pfsense.org/index.php?topic=108822.0