[Microsoft.Android.Templates] Add icons to templates

Fixes: https://dev.azure.com/devdiv/DevDiv/_workitems/edit/1714750

Context: https://github.com/dotnet/maui/blob/8e4450cbc14932a6c74aeb8b7bfee9c94eca18b0/src/Templates/src/templates/maui-mobile/.template.config/ide.host.json#L3

The way to specify an icon for a `dotnet new` template is to specify
an `icon` key within `.template.config/ide.host.json`.

Author: jonpryor

src/Microsoft.Android.Templates/android-activity/.template.config/ide.host.json

@@ -1,6 +1,7 @@
 {
     "$schema": "http://json.schemastore.org/ide.host",
+    "icon": "ide/icon.png",
     "appliesTo": "Android",
     "defaultItemExtension": "cs",
     "itemHierarchyPaths": [ "Android" ]
-}
+}

src/Microsoft.Android.Templates/android-activity/.template.config/ide/icon.png

@@ -0,0 +1,7 @@
+{
+    "$schema": "http://json.schemastore.org/ide.host",
+    "icon": "ide/icon.png",
+    "appliesTo": "Android",
+    "defaultItemExtension": "cs",
+    "itemHierarchyPaths": [ "Android" ]
+}

src/Microsoft.Android.Templates/android-bindinglib/.template.config/ide.host.json

@@ -1,6 +1,7 @@
 {
     "$schema": "http://json.schemastore.org/ide.host",
+    "icon": "ide/icon.png",
     "appliesTo": "Android",
     "defaultItemExtension": "xml",
     "itemHierarchyPaths": [ "Android" ]
-}
+}

src/Microsoft.Android.Templates/android-bindinglib/.template.config/ide/icon.png

@@ -0,0 +1,7 @@
+{
+    "$schema": "http://json.schemastore.org/ide.host",
+    "icon": "ide/icon.png",
+    "appliesTo": "Android",
+    "defaultItemExtension": "cs",
+    "itemHierarchyPaths": [ "Android" ]
+}

src/Microsoft.Android.Templates/android-layout/.template.config/ide.host.json

@@ -0,0 +1,7 @@
+{
+    "$schema": "http://json.schemastore.org/ide.host",
+    "icon": "ide/icon.png",
+    "appliesTo": "Android",
+    "defaultItemExtension": "cs",
+    "itemHierarchyPaths": [ "Android" ]
+}