Use Mixins for simplification

- Split Sw360Error in independent class
- Split the main codebase in Mixins to reduce size of main source code
This makes clearer and easier to update specific sw360 areas

Signed-off-by: Helio Chissini de Castro <helio.chissini-de-castro@bmw.de>

Author: Helio Chissini de Castro

poetry.lock

@@ -31,6 +31,7 @@ flake8 = ">=3.7.8"
 responses = "^0.12.1"
 pytest = "^6.1.2"
 coverage = "^5.3"
+types-requests = "^2.27.11"
 
 [build-system]
 requires = ["poetry>=0.12"]

pyproject.toml

@@ -9,4 +9,5 @@
 
 __version__ = (1, 2, 0)
 
-from .sw360_api import SW360, SW360Error  # noqa: F401
+from .sw360_api import SW360  # noqa: F401
+from .sw360error import SW360Error  # noqa: F401