Decide for one json serializer package

[SolidProgramming]

Regarding the issue #2540 i found out that we often use two json serializers: Newtonsoft.Json and System.Text.Json.
Because of that we always need to add two attribute classes when defining custom property naming for serialization/deserialization. E.g.: [JsonProperty("sid"), JsonPropertyName("sid")]

@abarz722 & @tpurschke do you see any potential caveats im missing? The RestSharp Rest Client is using it's own namespace for the serializers...

I would go for System.Text.Json package because this is no extra package and directly maintained by MS. But System.Text.Json offers fewer flexibility that we might need. If yes, we go for Newtonsoft

[tpurschke]

@NilsPur says: class System.Text.Json.Serialization can be removed
best to auto-remove all JsonPropertyName occurances in our code using regular expressions

[SolidProgramming]

@NilsPur says: class System.Text.Json.Serialization can be removed best to auto-remove all JsonPropertyName occurances in our code using regular expressions

Alright. Should be no problem.