* Deprecate backwards compatibility methods that were retained during v9 rework
* Upgrade API and rename a few things for PEP-8
* Switch to HttpCase for tests
* Switch to isolated build
* [ADD] base_external_system: Implement interface/adapter for external systems
* base_external_system: Fix OS model, add inherits, add validate
* base_external_system: Usability and private key pass
* base_external_system: Use contextmanager in adapter client
* base_external_system: Move contextmanager to interface
* base_external_system: Include contextmanager on adapter and system
* base_external_system: Unify client
* Use password widget for password field
* Add tests & security
* Fix lint
* Add plaintext note
OCA Transbot
Dave Lasley