Docstring update (#58)

* migrate docstrings from reST to google format

* add raises note

Also change behaviour of the `from_option` method to fallback to
disabled instead of raising exception on unknown option

* fix part of warnings for sphinx

* make identation a bit more readable

* review fixes

* add verbose description for properties to make them parsed by sphinx extenstion

* add demo sphinx generator

docs/source/ahriman.core.repository.rst

@@ -0,0 +1,59 @@
+ahriman.core.repository package
+===============================
+
+Submodules
+----------
+
+ahriman.core.repository.cleaner module
+--------------------------------------
+
+.. automodule:: ahriman.core.repository.cleaner
+   :members:
+   :no-undoc-members:
+   :show-inheritance:
+   :private-members:
+
+ahriman.core.repository.executor module
+---------------------------------------
+
+.. automodule:: ahriman.core.repository.executor
+   :members:
+   :no-undoc-members:
+   :show-inheritance:
+   :private-members:
+
+ahriman.core.repository.properties module
+-----------------------------------------
+
+.. automodule:: ahriman.core.repository.properties
+   :members:
+   :no-undoc-members:
+   :show-inheritance:
+   :private-members:
+
+ahriman.core.repository.repository module
+-----------------------------------------
+
+.. automodule:: ahriman.core.repository.repository
+   :members:
+   :no-undoc-members:
+   :show-inheritance:
+   :private-members:
+
+ahriman.core.repository.update\_handler module
+----------------------------------------------
+
+.. automodule:: ahriman.core.repository.update_handler
+   :members:
+   :no-undoc-members:
+   :show-inheritance:
+   :private-members:
+
+Module contents
+---------------
+
+.. automodule:: ahriman.core.repository
+   :members:
+   :no-undoc-members:
+   :show-inheritance:
+   :private-members: