Fugue API

Add fugue API (#396)

* Add fugue interfaceless util functions

* update tests

* fix test coverage

* fix numpy brreaking change

* update backends for utils functions

* fix

* update qpd

* refactor code

* Add test suite for express functions

* add engine level utils

* refactor code

* add engine operations

* update type annotations and docs

* lint

* top api docs

* Refactor ibis, add fugue sql api

* make duckdb columns encoded

* improve test coverage

* fix tests

* refactor SQLEngine

* fix ray tests and coverage

* fix tests, add fugue.default.partitions

* update docs

* fix tests

* fix test coverage

* update docs

* add all sql api functions

* lint

* add join functions

* Make PartitionSpec more flexible