Add installation docs (#465)

Part of pulumi/home#3598

Generates a single index.md file with relevant content.

docs/_index.md

@@ -0,0 +1,175 @@
+---
+title: Mailgun Provider
+meta_desc: Provides an overview on how to configure the Pulumi Mailgun provider.
+layout: package
+---
+## Installation
+
+The mailgun provider is available as a package in all Pulumi languages:
+
+* JavaScript/TypeScript: [`@pulumi/mailgun`](https://www.npmjs.com/package/@pulumi/mailgun)
+* Python: [`pulumi-mailgun`](https://pypi.org/project/pulumi-mailgun/)
+* Go: [`github.com/pulumi/pulumi-mailgun/sdk/v3/go/mailgun`](https://github.com/pulumi/pulumi-mailgun)
+* .NET: [`Pulumi.Mailgun`](https://www.nuget.org/packages/Pulumi.Mailgun)
+* Java: [`com.pulumi/mailgun`](https://central.sonatype.com/artifact/com.pulumi/mailgun)
+## Overview
+
+The Mailgun provider is used to interact with the
+resources supported by Mailgun. The provider needs to be configured
+with the proper credentials before it can be used.
+
+Use the navigation to the left to read about the available resources.
+## Example Usage
+
+{{< chooser language "typescript,python,go,csharp,java,yaml" >}}
+{{% choosable language typescript %}}
+```yaml
+# Pulumi.yaml provider configuration file
+name: configuration-example
+runtime: nodejs
+config:
+    mailgun:apiKey:
+        value: 'TODO: "${var.mailgun_api_key}"'
+
+```
+```typescript
+import * as pulumi from "@pulumi/pulumi";
+import * as mailgun from "@pulumi/mailgun";
+
+// Create a new domain
+const _default = new mailgun.Domain("default", {});
+```
+{{% /choosable %}}
+{{% choosable language python %}}
+```yaml
+# Pulumi.yaml provider configuration file
+name: configuration-example
+runtime: python
+config:
+    mailgun:apiKey:
+        value: 'TODO: "${var.mailgun_api_key}"'
+
+```
+```python
+import pulumi
+import pulumi_mailgun as mailgun
+
+# Create a new domain
+default = mailgun.Domain("default")
+```
+{{% /choosable %}}
+{{% choosable language csharp %}}
+```yaml
+# Pulumi.yaml provider configuration file
+name: configuration-example
+runtime: dotnet
+config:
+    mailgun:apiKey:
+        value: 'TODO: "${var.mailgun_api_key}"'
+
+```
+```csharp
+using System.Collections.Generic;
+using System.Linq;
+using Pulumi;
+using Mailgun = Pulumi.Mailgun;
+
+return await Deployment.RunAsync(() =>
+{
+    // Create a new domain
+    var @default = new Mailgun.Domain("default");
+
+});
+
+```
+{{% /choosable %}}
+{{% choosable language go %}}
+```yaml
+# Pulumi.yaml provider configuration file
+name: configuration-example
+runtime: go
+config:
+    mailgun:apiKey:
+        value: 'TODO: "${var.mailgun_api_key}"'
+
+```
+```go
+package main
+
+import (
+	"github.com/pulumi/pulumi-mailgun/sdk/v3/go/mailgun"
+	"github.com/pulumi/pulumi/sdk/v3/go/pulumi"
+)
+
+func main() {
+	pulumi.Run(func(ctx *pulumi.Context) error {
+		// Create a new domain
+		_, err := mailgun.NewDomain(ctx, "default", nil)
+		if err != nil {
+			return err
+		}
+		return nil
+	})
+}
+```
+{{% /choosable %}}
+{{% choosable language yaml %}}
+```yaml
+# Pulumi.yaml provider configuration file
+name: configuration-example
+runtime: yaml
+config:
+    mailgun:apiKey:
+        value: 'TODO: "${var.mailgun_api_key}"'
+
+```
+```yaml
+resources:
+  # Create a new domain
+  default:
+    type: mailgun:Domain
+```
+{{% /choosable %}}
+{{% choosable language java %}}
+```yaml
+# Pulumi.yaml provider configuration file
+name: configuration-example
+runtime: java
+config:
+    mailgun:apiKey:
+        value: 'TODO: "${var.mailgun_api_key}"'
+
+```
+```java
+package generated_program;
+
+import com.pulumi.Context;
+import com.pulumi.Pulumi;
+import com.pulumi.core.Output;
+import com.pulumi.mailgun.Domain;
+import java.util.List;
+import java.util.ArrayList;
+import java.util.Map;
+import java.io.File;
+import java.nio.file.Files;
+import java.nio.file.Paths;
+
+public class App {
+    public static void main(String[] args) {
+        Pulumi.run(App::stack);
+    }
+
+    public static void stack(Context ctx) {
+        // Create a new domain
+        var default_ = new Domain("default");
+
+    }
+}
+```
+{{% /choosable %}}
+{{< /chooser >}}
+## Configuration Reference
+
+The following configuration inputs are supported:
+
+* `apiKey` - (Required) Mailgun API key