Endpoint for item bonus stats

## Data generation

To generate [the script](https://gist.github.com/Mischanix/d8f7a5f67d1b012987db#file-dump_bonus_stats-lua), use `s_bonusStatStringTags`, `BONUS_STAT_START`, and `BONUS_STAT_MAX` from the client source tree (probably available in `WoW/Source/Ui/GameUI.cpp` but I can't be sure). If `s_bonusStatStringTags` is defined by brace initialization, you can probably copy-paste that and adjust the indexing at [line 85](https://gist.github.com/Mischanix/d8f7a5f67d1b012987db#file-dump_bonus_stats-lua-L85) to read `local mod = bonusStats[i + 1]`. The script also requires `Interface/FrameXML/GlobalStrings.lua` from the appropriate localized client data directory to be present in the same directory when ran. From there it's just a matter of running the script and converting the tsv output to whatever format you wanna consume.
## Documentation sample
### Item Bonus Stats

The item bonus stats data API provides a mapping from bonusStat id to name.

URL: `/api/wow/data/item/bonusStats`
#### _Example Data_
- [sample_18764.json](https://gist.github.com/Mischanix/d8f7a5f67d1b012987db#file-sample_18764-json)