LBRY Comment Server v2

This is a rewrite & update of the server written by myself and Grayson Burton here

A lot of the design is more or less the same with the original, except this version focuses less on performance and more on scalability.

Rewritten with python because it's easier to adjust and maintain. Instead of doing any multithreading, this implementation just delegates a single database connection for write operations.

The server was originally implemented with aiohttp and uses aiojobs for scheduling write operations. As pointed out by several people, Python is a dinosaur in comparison to SQLite's execution speed, so there is no sensibility in multi-threading from the perspective of the server code itself.

The schema for