Guide: How to build a simple SLP app

[blockparty-sh]

Intro to slpdb, slpsocket, and slpjs

Create a wallet, send tokens from it, see query those tokens using slpsocket and slpdb

Targetting first time SLP developers

[yume-arasaki]

should add a section about future architecture, and forwarning that SLP DB relies on Bitbox which runs on bcom rest API and no longer maintained?