Refactor to use Dapper.ISqlBuilder internally

[TroySchmidt]

Dapper.ISqlBuilder internally provides a better mechanism of using SQL templates and the ability to add in joins for multimapping. Refactoring to use this would allow us to better develop completely dynamic GraphQL SQL queries.

• [x] Create SqlQuery class
• [ ] Write unit tests to cover the most common scenarios
• [ ] Make sure SqlQuery allows to easily convert GraphQL query to SQL query using this new class
• [ ] Feature parity with SqlExpression
• [ ] Replace SqlExpression with SqlQuery

The important piece is just like .Where() and .Select() we need a similar mechanism to add the join and the custom fields that are to be selected.

Inspiration can be drawn from Dapper.GraphQL implementation of using SqlBuilder for multimapping.

[TroySchmidt]

@tswacast I started a branch for this and created a new class SqlQuery. The intent is that this class will be used for building queries using both the Dommel.Resolvers and Dapper.SqlBuilder. Once the class is implemented, we can then add the join query to the IForeignKeyResolver interface and class. Currently there is convention based relationships and instead of letting those be determined in DommelMapper.Multimap, they will be in the foreign key resolver. This will allow us to later add methods to Dapper.Fluentmap.Dommel to allow for custom join queries.