Story - Schema validator

[fedefernandez]

As part of this story we should:

• Spike Spike - Schema Validator #47
• Define the keyspace and table models - Issue Define the table model #24
• Add a mechanism (through implicits?) for retrieving schema information, providing different strategies (local schema sql, remote connection to the db, ...) - Issue Mechanism for retrieving schema information #27
• Add a schema parser for keyspaces - PR Keyspace schema parser #15
• Add a scheme parser for tables - Not needed (Implement a local schema provider based on Troy #49)
• Implement a local schema sql provider - Issue Implement a local schema provider based on Troy #49
• Implement a remote scheme provider - Issue Implement a remote scheme provider #51