doc: Readme for tbp-consumer-api

[Luisnadachi]

Hi guys, I want to contribute in the project but I had a lot of trouble to build the api. I think the project need a README that describe how to build and up the project. The points I was by myself are:

• Build the cargo of rust
• Installing the scyllaDB
• Build the keyspace of twitch

I thought about writing the installation but I got stuck on this error:

thread 'main' panicked at src/main.rs:30:84:
called `Result::unwrap()` on an `Err` value: Os { code: 2, kind: NotFound, message: "No such file or directory" }

[DanielHe4rt]

I'll work on it today.

[DanielHe4rt]

Or maybe tomorrow LUL