[binderator] Add binding type and use it to remove 'gson' template. (#…

…941)

Some of the final pieces needed to start removing package-specific templates:

- We use the top level `mavenRepositoryType` to default all packages to Google's Maven, and then use the templates to override this to `MavenCentral`. Without templates we will need to specify this directly on the artifact, so add support for an artifact level `mavenRepositoryType`.

- We have several different "types" of packages that we create today:
  - `EmbeddedJar` - Basic use of `<EmbeddedJar>` to include the Java payload in the NuGet package next to the managed bindings `.dll`. (This is equivalent to the preferred `<AndroidLibrary>` in .NET 6+.)
  - `Targets` - Uses `<InputJar>` to create the binding `.dll` and `<None>` to add the Java payload manually into the NuGet package and uses a `.targets` file to add it to the Android application.
  - `NoBindings` - Uses `<None>` to add the Java payload manually into the NuGet package and uses a `.targets` file to add it to the Android application. Does not create managed bindings.
  - `XBD` - Uses `<InputJar>` to create the binding `.dll`. The Java payload is not included in the NuGet package. Instead a `.targets` file is used to download the payload at compile time using `Xamarin.Build.Download`.

The default package type is `targets`, which is what the current default template uses. That is, this is the one that all AndroidX packages currently use.

To specify a different package type, we add a new artifact level `type` attribute. The only currently supported value for this is `androidlibrary` which provides the `EmbeddedJar` package type behavior.

As a proof of concept, migrate `GoogleGson` from the `gson` template to the default template.

### Results
Before:
```json
{
  "groupId": "com.google.code.gson",
  "artifactId": "gson",
  "version": "2.11.0",
  "nugetVersion": "2.11.0.1",
  "nugetId": "GoogleGson",
  "dependencyOnly": false,
  "templateSet": "gson"
}
```
![image](https://github.com/user-attachments/assets/968d3251-52fc-449f-a629-f28c86b44321)

After:
```json
{
  "groupId": "com.google.code.gson",
  "artifactId": "gson",
  "version": "2.11.0",
  "nugetVersion": "2.11.0.1",
  "nugetId": "GoogleGson",
  "dependencyOnly": false,
  "type": "androidlibrary",
  "mavenRepositoryType": "MavenCentral"
}
```
![image](https://github.com/user-attachments/assets/97bed63c-10c3-4827-992c-669f153f8c12)

config.json

@@ -2455,7 +2455,8 @@
         "nugetVersion": "2.11.0.1",
         "nugetId": "GoogleGson",
         "dependencyOnly": false,
-        "templateSet": "gson"
+        "type": "androidlibrary",
+        "mavenRepositoryType": "MavenCentral"
       },
       {
         "groupId": "com.google.crypto.tink",
@@ -2947,7 +2948,7 @@
         "nugetVersion": "121.5.0.1",
         "nugetId": "Xamarin.GooglePlayServices.Cast.Framework",
         "dependencyOnly": true
-      },      
+      },
       {
         "groupId": "com.google.android.gms",
         "artifactId": "play-services-cronet",
@@ -3193,24 +3194,6 @@
           }
         ]
       },
-      {
-        "name": "gson",
-        "mavenRepositoryType": "MavenCentral",
-        "templates": [
-          {
-            "templateFile": "templates/gson/Project.cshtml",
-            "outputFileRule": "generated/{groupid}.{artifactid}/{groupid}.{artifactid}.csproj"
-          },
-          {
-            "templateFile": "source/AndroidXNuGetReadMe.cshtml",
-            "outputFileRule": "generated/{groupid}.{artifactid}/readme.md"
-          },
-          {
-            "templateFile": "source/AndroidXSolutionFilter.cshtml",
-            "outputFileRule": "generated/{groupid}.{artifactid}/{groupid}.{artifactid}.slnf"
-          }
-        ]
-      },
       {
         "name": "auto-value",
         "mavenRepositoryType": "MavenCentral",

source/AndroidXProject.cshtml

@@ -50,7 +50,7 @@
 
   <!-- Packaging files -->
   <ItemGroup>
-    @if (Model.ShouldIncludeArtifact) {
+    @if (Model.ShouldIncludeArtifact && Model.Type == AndroidBinderator.BindingType.Targets) {
     <None Include="@(Model.NuGetPackageId).targets" Pack="True" PackagePath="@@(AndroidXNuGetTargetFolders)" />
     }
     <None Include="..\..\source\PackageLicense.md" Pack="True" PackagePath="LICENSE.md" />
@@ -96,6 +96,7 @@
     </TransformFile>
   </ItemGroup>
 
+@if (Model.Type == AndroidBinderator.BindingType.Targets) {
   @if (@Model.MavenArtifacts.Count > 0) {
   <!-- Java artifacts to bind -->
   <ItemGroup>
@@ -138,6 +139,16 @@
       }
     }
   </ItemGroup>
+}
+
+@if (Model.Type == AndroidBinderator.BindingType.AndroidLibrary) {
+  <ItemGroup>
+      @foreach (var art in @Model.MavenArtifacts)
+      {
+    <AndroidLibrary Include="..\..\externals\@(art.MavenGroupId)\@(art.MavenArtifactId).@(art.MavenArtifactPackaging)" />
+      }
+  </ItemGroup>
+}
 
   <!-- ProjectReferences -->
   <ItemGroup>