Add type hints and clean up documentation for encoders and decoders (#367)

* Add type hint for _Encoder

* Add type hint for _Decoder

* Rename type aliases to InnerEncoder and InnerDecoder

* Fix docstrings and add some additional type hints.

* Remove Context class

* Fix get_type_default docs

* Remove notes file

* Add WriteFunction type alias

* Rename InnerEncoder to Encoder and InnerDecoder to Decoder

* Rename EncoderFactory to EncoderConstructor and DecoderFactory to DecoderConstructor

* Rename EncoderConstructor to PartialEncoderConstructor and DecoderConstructor to PartialDecoderConstructor

* Add EncoderConstructor and DecoderConstructor and cast where needed

* Only use typing_extensions if less than Python 3.10

* Update some type hints

* Update documentation to stop using factory

* Add Key TypeVar

* Clarify use of new_default

* Type hints for is_packed etc

* Change Key to FieldDescriptor

* Use ValueError instead of Exception.

* Match _vector_decoder return type for _new_default

Author: dixonjoel

ni_measurementlink_service/_internal/parameter/metadata.py

@@ -5,9 +5,7 @@
 
 from google.protobuf import type_pb2
 
-from ni_measurementlink_service._internal.parameter.serialization_strategy import (
-    Context,
-)
+from ni_measurementlink_service._internal.parameter import serialization_strategy
 from ni_measurementlink_service.measurement.info import TypeSpecialization
 
 
@@ -60,13 +58,17 @@ def validate_default_value_type(parameter_metadata: ParameterMetadata) -> None:
         return None
 
     expected_type = type(
-        Context.get_type_default(parameter_metadata.type, parameter_metadata.repeated)
+        serialization_strategy.get_type_default(
+            parameter_metadata.type, parameter_metadata.repeated
+        )
     )
     display_name = parameter_metadata.display_name
     enum_values_annotation = get_enum_values_annotation(parameter_metadata)
 
     if parameter_metadata.repeated:
-        expected_element_type = type(Context.get_type_default(parameter_metadata.type, False))
+        expected_element_type = type(
+            serialization_strategy.get_type_default(parameter_metadata.type, False)
+        )
         _validate_default_value_type_for_repeated_type(
             default_value,
             expected_type,