docs: add data types and quick start

[DanielHe4rt]

I was looking after the Data Types cheatsheet and after a while I found at GoCQLX Example file. IMHO this information should be more straightforward as possible.

Also added an "Quick Start" section to give some orientation for a driver newcomer to see it run ASAP.

New Content:

• Added a "Quick Start" section with instructions on how to spawn a ScyllaDB instance using Docker and create a new connection using ScyllaDB GoCQL. (README.md)
• Introduced a "Data Types" section listing all ScyllaDB types reflected in the GoCQL environment along with their corresponding Go types. (README.md)

[DanielHe4rt]

@dkropachev @sylwiaszunejko please, review when you have some time.