Spell List Refactor (making spell creation easier)

[stoneharry]

Make spell creation a lot easier by improving the spell selection list.

Issue: #206

• [x] Make Spell Selection List a component
• [x] Update new spell to not do a full rebuild of the list
• [x] Update delete spell to not do a full rebuild of the list
• [x] Implement context menu support for spell selection list
• [x] Implement delete spell context menu
• [x] Implement copy spell context menu
• [x] Implement duplicate spell context menu
• [ ] Remove new/delete spell buttons from window header (might want to keep this)
• [x] Localise strings

Also priotitises the spell DBC import/export when selected in the UI by using the existing DB adapter.