Fix/operation variable bases

OperationVariable isn't actually Referrable according to DotAAS. The inheritance from SubmodelElement was a mistake by us.

added 46 commits

• e3a441f8 - model.adapter: first version of json serialization
• e919dec4 - adapter.json_adapter: using enum members instead of their names
• ec9c9afa - adapter.json_adapter: merge individual functions for abstract base classes in...
• cabd915f - adapter.json_adapter: delete lang_string_set_to_json because no longer needed
• fc452ef4 - adapter.json_adapter: add docstrings to all classes and functions, add obj to...
• 72ae7796 - adapter.json_adapter: make ordered attribute in submodel_element_collection_to_json optional
• bc012eff - adapter.json_adapter: add comment for mapping of enum values to json strings
• c7b26dee - model, adapter: make kind optional
• de23cc37 - model: fixed build error
• cae3b3f6 - adapter.json: Add type hints
• f8542c58 - adapter.json: Fix bugs
• 11c53a05 - adapter.json: Remove unrequired transformation function for SubmodelElement
• 36937373 - model, adapter: undo make kind optional
• 1cf56e1b - adapter: restructuring
• 37b37e89 - test.adapter.json: first test for validation
• 0c0b8a36 - adapter.json: Clean up test
• 2fa65a0a - adapter.json: Fix serialization of 'semanticId'
• d1323050 - model: Change BlobType from bytearray to bytes (which is more generic)
• 71c4430e - adapter.json: Add first version of json deserialization functionality
• 54988918 - Add pip requirements.txt file, use it in CI
• 53557b16 - adapter.json: Fix deserialization of Asset: Use _amend_abstract_attributes
• 79077466 - adapter.json: Add differentiated failsafe and strict mode for JSON deserialization
• 26569fb8 - adapter.json: Improve documentation and fix codestyle warnings
• 5c64e21c - adapter.json: Improve Exceptions' messages
• c76f3429 - adapter.json: Add read_json_aas_file()
• f158bc50 - aas.examples: add example for a nearly complete asset administration shell with all its elements
• c4678b52 - Merge branch 'master' into features/json_adapter
• 58783457 - adapter.json: Fix changed name of KeyElements.ANNOTATED_RELATIONSHIP_ELEMENT
• fd058a92 - adapter.json: Fix usage of Reference and new AASReference
• 23749c7e - adapter.json: Fix deserialization of View with new base classes
• 0f196e30 - adapter.json: Fix serialization of Blob with base64 encoding
• 1405e71d - adapter.json: Fix serialization of LangStringSet
• 724f7861 - adapter.json: Fix modelType attribute for derived classes
• 9651de21 - adapter.json: Fix serialization of Capability
• c4f1625a - examples: Fix type error
• 72c672ec - adapter.json: Use model.KEY_ELEMENTS_CLASSES instead of local copy
• 6ff3699a - Add license headers to new files
• a98ed782 - adapter.json: Fix Reference Key type check in deserialization
• 7f3d49b3 - adapter.json: Add deserialization of AnnoatedRelationshipElement
• 76419285 - adapter.json: Allow missing SubmodelElementCollection.ordered attribute
• 50ca8fc3 - adapter.json: Fix serialization of Property.valueType
• a0d77106 - model: Add OperationVariable to KeyElements enum
• 597e8e5d - test: Add json deserialization to the full example test
• 84505ba0 - json.serialization: add write_aas_to_json_file function
• 4cd53936 - adapter.json.json_serialization: add modul docstring
• b6dc493d - model: Fix incompliant inheritance of OperationVariable from SubmodelElement

Compare with previous version

added 30 commits

• b6dc493d...fd6a5209 - 29 commits from branch master
• 0fee9b12 - model: Fix incompliant inheritance of OperationVariable from SubmodelElement

Compare with previous version

merged

mentioned in commit 2151515b