Added Protection paladin and minor improvements to Retribution

[himea-saito]

Changes Made

Paladin:

• Added support for Protection paladin spec
• Made minor changes to Retribution options to make more sense
• Corrected some ability registers to better reflect how the function in game

Protection Specific:

• Used https://wowtbc.gg/cata/class-guides/protection-paladin/ as a baseline for rotation
• Added logic to recommend defensives based on settings

Further Review Needed / Known Issues:

• Currently, potions are not displayed in the selection menu.
• Holy APL is not updated.
• Tier sets and other class-specific item effects aren't added.