Sqloquent

- New method `HashedModel.preimage` to get the preimage of the sha256 id in the
form of the bytes-serialized non-id, non-excluded columns and their values.
- Method `HashedModel.generate_id` now calls `preimage` internally.

- Updated migration system to use the `quote_identifier` and `quote_sql_str_value`
functions for quoting identifiers and string values.
- Updated `quote_identifier` to properly quote components in a multi-part
identifier and raise ValueError when a component has an unmatched double
quotation mark or when the identifier contains a single quote.
- Added new unit tests for `quote_identifier` and `quote_sql_str_value`

- Updated query builders to quote identifiers and escape string quotes

- Added support for boolean columns in migration system
- Added casting for boolean columns in query builders
- Added new syntax for declaring default column values on classes
- Added new syntax for declaring default column values in migrations
- Updated migration system to quote identifiers
- Updated tools for generating models and migrations from models to support
booleans and default values

- Fixed issues with `data_original` property interface (relations, etc.)
- Fixed bugs in `to_sql` method of `SqlQueryBuilder` and `AsyncSqlQueryBuilder`
- Added new syntax for QueryBuilder methods (can not use kwargs to specify
multiple conditions of the same type)

- Added change tracking to `SqlModel`, `AsyncSqlModel`, and subclasses
- Added event str as keyword arg for event hook calls: `hook(cls, *args, event=event, **kwargs)`
- Standardized `invoke_hooks` calls to include all non-event name args as kwargs;
- `invoke_hooks` calls callbacks with `(cls, *args, **kwargs)`, but `*args` will be empty