Add More Documentation

[omervk]

It would be great to add a bunch of documentation:

• Design of each part of the system (from TableOperations to Expressions, etc.)
• Tradeoffs taken in the design of the table format
• Context bounds - what is and isn't in scope for Iceberg
• What you need to do to replace Hive with your own metastore
• Bootstrapping your own use of Iceberg
• Reasoning for limiting what's possible with Avro schemas

[omervk]

@rdblue I think this may be the most pressing issue for the project, especially since it's now an Apache project (incubating). I'll be happy to take up some of it if you like.

[rdblue]

@omervk, it would be great to have docs contributions! We just created a mkdocs site for the Iceberg incubator project, so you can add docs through pull requests to site on the Iceberg incubator project.

[omervk]

Great! How will you be working with the other repo? Archiving the current one? Will you be migrating the issues, too?

[rdblue]

Yes, I'll migrate the issues and then turn off issue tracking here.