Ziggurat-foundations

**This is the last release that is compatible with Python versions older than 3.6**

Added
* pyramid extensions can now accept `session_provider_callable` not only as a path to callable but
also as plain callable object
* tests for pyramid extensions
Changed
* Become compatible with sqlalchemy 1.4.x
* Allow obtaining node resource by model name 70 (thanks Francis Charette Migneault)
* remove deprecated base model code
* reduce warnings generated
* prepare for pyramid versions higher than 2.0
Fixed
* missing argument in specific permission fetching codepath 69

Added
* pyramid extensions can now accept `session_provider_callable` not only as a path to callable but
also as plain callable object
* tests for pyramid extensions
Changed
* fixed deprecated usage of `set_request_property` (thanks Francis Charette Migneault)

Fixed
* Fixed migrations under Mysql 8.x

Changed
* [Breaking] Most of deprecated model methods got removed, please use services instead
* [Breaking] ziggurat_model_init has now explicit order of model classes set

Changed
* Use pbkdf2_sha256 by default (bcypt hashes will work and will be migrated on first login for users)

**Important**

By default `check_password` will migrate your existing bcrypt hashes to pbkdf2_sha256, if you want to keep bcrypt,
you can either pass `passwordmanager_schemes` list to `ziggurat_model_init` or use your own passwordmanager.

Changed
* Fixed some minor issues that resulted in bad migrations when someone used `autogenerate in alembic`
* Added a way to read sqlalchemy.url from environment variable (thanks René Jochum)