Add sql service

[sebinside]

Description

Add service to connect to mysql databases. There are multiple commonly used npm packages available.

References

https://www.npmjs.com/package/knex

[promasu]

We should add a general service for SQL and use adapters for the specific implementations like sqlite, pgsql, mysql

[LarsVomMars]

In this case we should also consider NoSQL databases like Mongo and Redis.

Otherwise, I would recommend using the mariadb package for mysql connection instead due to its performance benefits.

[promasu]

NoSQL Databases are a bit out of scope aren't they?