Get rid of Newtonsoft.Json everywhere but the HTTP abstractions

src/Bot/Bot.csproj

@@ -27,7 +27,6 @@
         <PackageReference Include="HtmlAgilityPack" Version="1.11.36" />
         <PackageReference Include="JikanDotNet" Version="1.6.0" />
         <PackageReference Include="MtgApiManager.Lib" Version="1.2.2" />
-        <PackageReference Include="Newtonsoft.Json" Version="12.0.3" />
         <PackageReference Include="PokeApi.NET" Version="1.1.2" />
         <PackageReference Include="Sentry" Version="3.9.2" />
     </ItemGroup>

src/Bot/Commands/Integrations/LolMmr/LolMrrInfoDto.cs

@@ -1,10 +1,11 @@
-using Newtonsoft.Json;
+using System.Text.Json.Serialization;
 
 namespace Geekbot.Bot.Commands.Integrations.LolMmr
 {
     public class LolMrrInfoDto
     {
-        [JsonProperty(NullValueHandling = NullValueHandling.Ignore)]
+        [JsonPropertyName("avg")]
+        [JsonIgnore(Condition = JsonIgnoreCondition.WhenWritingNull)]
         public decimal Avg { get; set; } = 0;
     }
 }

src/Bot/Commands/Utils/Corona/CoronaApiCountryResponseDto.cs

@@ -1,19 +1,19 @@
-using Newtonsoft.Json;
+using System.Text.Json.Serialization;
 
 namespace Geekbot.Bot.Commands.Utils.Corona
 {
     public record CoronaApiCountryResponseDto
     {
-        [JsonProperty("country")]
+        [JsonPropertyName("country")]
         public string Country { get; init; }
 
-        [JsonProperty("cases")]
+        [JsonPropertyName("cases")]
         public decimal Cases { get; init; }
 
-        [JsonProperty("deaths")]
+        [JsonPropertyName("deaths")]
         public decimal Deaths { get; init; }
 
-        [JsonProperty("recovered")]
+        [JsonPropertyName("recovered")]
         public decimal Recovered { get; init; }
     }
 }