Hobbit-core

* Add CustomParser for automatically trim leading/trailing whitespace from argument values(`from hobbit_core.webargs import use_args, use_kwargs`).
* Add `HOBBIT_UPPER_SEQUENCE_NAME` config for upper db's sequence name.
* Fixs some err in template.

* Add `db.BaseModel` for support Oracle id sequence.

* Add template for 4-layers (view、schema、service、model).
* Add options api for query all consts defined in `app/models/consts`.
* Add `create` command to generate a csv file that defines some models to use in the `gen` command.
* Removed example code.
* Split hobbit cmd and hobbit_core lib, now install cmd should be `pip install "hobbit-core[hobbit,hobbit_core]"`.
* Remove flask_hobbit when import (`hobbit_core.flask_hobbit.db import transaction` --> `from hobbit_core.db import transaction`).
* Enhance gen cmd: now can auto create CRUD API and tests.
* Fix typo.
* Update some test cases.

* Add `create` command to generate a csv file that defines some models to use in the `gen` command.
* Refactor hobbit cmds.

* Support gen models from a csv file.

* Fix typo in gen cmd doc.
* Update some test cases.