Implemented option to use different providers for checking item prices

[ForsakenNGS]

• Added various data that can be grabbed from the official poe trading api and wiki
• Added advanced item parser (including item mods, min-/max-rolls, sockets, ...)
• Added first implementation of price checking for the official poe trading api
  • "src/resource/modPseudoMappings.json" contains some rules for combining certain mods into pseudo-mods when searching or ignoring some in certain cases
  • "src/modules/poetrade.js" function "getSearchQuery" contains the core logic for setting up the search parameters
• Added the possibility to add multiple providers for price estimations, which will automatically fallback on failure
• Added notice about max rolled mods (always relative to the mod tier)

Here we go again ;-) I refactored a lot and extracted the most complex functionality into it's seperate npm module. (See https://github.com/ForsakenNGS/PoeData - documentation is still a todo, but the classes are pretty clean imho)

I also added automatic fallbacks in case of failure, a cleaner settings section and a few optimizations for the search e.g. an implementation for scarab search (see #31 )

If there are still issues, questions or constructive feedback feel free to contact me :)

[Jotune]

This looks great ! Any update on accepting the pull request ?