Rule-engine

* [StringSyntaxError](https://zerosteiner.github.io/rule-engine/rule_engine/errors.html#rule_engine.errors.StringSyntaxError) is now raised for invalid string literals
* [FunctionCallError](https://zerosteiner.github.io/rule-engine/rule_engine/errors.html#rule_engine.errors.FunctionCallError) is now raised when a typed function returns an incompatible value
* Added the new [BYTES](https://zerosteiner.github.io/rule-engine/rule_engine/types.html#rule_engine.types.DataType.BYTES) data type
* Added some new data attributes
* Added starts_with and ends_with to [ARRAY](https://zerosteiner.github.io/rule-engine/rule_engine/types.html#rule_engine.types.DataType.ARRAY), and [STRING](https://zerosteiner.github.io/rule-engine/rule_engine/types.html#rule_engine.types.DataType.STRING)

* Added the `$range` builtin function
* Added the `rule_engine.parser.utilities` module with a few functions and documentation

* Added the `is_nan` attribute for `FLOAT` values

* Added attributes for coercion of types to themselves, e.g. `to_str` for `STRING` values

* Added the `$abs` builtin function
* Added support to `from_type` Python’s type hints