[CSharp] feat!: add useDateOnly flag (#17471)

* feat: DateOnly for client

* fix: generated doc for csharp

* doc: fix generators README for csharp

* add DateOnly option for aspnet

* refactor: update csharp docs

* refactor: fix typo

* finish

* finish

* finish

* regenerate

* rebuild and regenerate

* fix build error

* finish

* revert path

* regenerate

* remove exceed samples

* regenerate

* add DateOnly to nullable

* remove obsolete file from list

* update test files list

* remove obsolete sample build

* revert manual tests

* revert samples to master and regenerate

* remove new samples

* remove eol

* remove eol

* add new specs

* try fix test

* update tests

* update files

* remove eol

* revert

* remove eol

* regenerate

* add net6+ support to aspnetcore

* add jobs

samples/client/petstore/csharp/OpenAPIClient-generichost-net6.0-nrt-useSourceGeneration/docs/models/DateOnlyClass.md

@@ -4,7 +4,7 @@
 
 Name | Type | Description | Notes
 ------------ | ------------- | ------------- | -------------
-**DateOnlyProperty** | **DateTime** |  | [optional] 
+**DateOnlyProperty** | **DateOnly** |  | [optional] 
 
 [[Back to Model list]](../../README.md#documentation-for-models) [[Back to API list]](../../README.md#documentation-for-api-endpoints) [[Back to README]](../../README.md)
 

samples/client/petstore/csharp/OpenAPIClient-generichost-net6.0-nrt-useSourceGeneration/docs/models/FormatTest.md

@@ -5,7 +5,7 @@
 Name | Type | Description | Notes
 ------------ | ------------- | ------------- | -------------
 **VarByte** | **byte[]** |  | 
-**Date** | **DateTime** |  | 
+**Date** | **DateOnly** |  | 
 **Number** | **decimal** |  | 
 **Password** | **string** |  | 
 **Binary** | **System.IO.Stream** |  | [optional] 

samples/client/petstore/csharp/OpenAPIClient-generichost-net6.0-nrt-useSourceGeneration/docs/models/NullableClass.md

@@ -8,7 +8,7 @@ Name | Type | Description | Notes
 **ArrayItemsNullable** | **List<Object>** |  | [optional] 
 **ArrayNullableProp** | **List<Object>** |  | [optional] 
 **BooleanProp** | **bool** |  | [optional] 
-**DateProp** | **DateTime** |  | [optional] 
+**DateProp** | **DateOnly** |  | [optional] 
 **DatetimeProp** | **DateTime** |  | [optional] 
 **IntegerProp** | **int** |  | [optional] 
 **NumberProp** | **decimal** |  | [optional] 

samples/client/petstore/csharp/OpenAPIClient-generichost-net6.0-nrt-useSourceGeneration/docs/models/RequiredClass.md

@@ -4,7 +4,7 @@
 
 Name | Type | Description | Notes
 ------------ | ------------- | ------------- | -------------
-**RequiredNotNullableDateProp** | **DateTime** |  | 
+**RequiredNotNullableDateProp** | **DateOnly** |  | 
 **RequiredNotnullableArrayOfString** | **List<string>** |  | 
 **RequiredNotnullableBooleanProp** | **bool** |  | 
 **RequiredNotnullableDatetimeProp** | **DateTime** |  | 
@@ -17,7 +17,7 @@ Name | Type | Description | Notes
 **RequiredNotnullableintegerProp** | **int** |  | 
 **RequiredNullableArrayOfString** | **List<string>** |  | 
 **RequiredNullableBooleanProp** | **bool** |  | 
-**RequiredNullableDateProp** | **DateTime** |  | 
+**RequiredNullableDateProp** | **DateOnly** |  | 
 **RequiredNullableDatetimeProp** | **DateTime** |  | 
 **RequiredNullableEnumInteger** | **int** |  | 
 **RequiredNullableEnumIntegerOnly** | **int** |  | 
@@ -26,9 +26,9 @@ Name | Type | Description | Notes
 **RequiredNullableOuterEnumDefaultValue** | **OuterEnumDefaultValue** |  | 
 **RequiredNullableStringProp** | **string** |  | 
 **RequiredNullableUuid** | **Guid** |  | 
-**NotRequiredNotnullableDateProp** | **DateTime** |  | [optional] 
+**NotRequiredNotnullableDateProp** | **DateOnly** |  | [optional] 
 **NotRequiredNotnullableintegerProp** | **int** |  | [optional] 
-**NotRequiredNullableDateProp** | **DateTime** |  | [optional] 
+**NotRequiredNullableDateProp** | **DateOnly** |  | [optional] 
 **NotRequiredNullableIntegerProp** | **int** |  | [optional] 
 **NotrequiredNotnullableArrayOfString** | **List<string>** |  | [optional] 
 **NotrequiredNotnullableBooleanProp** | **bool** |  | [optional]