Create authentication snippets

[JohnZoellerG]

Create snippets for Wear Auth DAC: https://developer.android.com/training/wearables/apps/auth-wear

[snippet-bot]

Here is the summary of changes.

You are about to add 7 region tags.

• wear/src/main/java/com/example/wear/snippets/auth/CredentialManager.kt:50, tag android_wear_credential_manager_secondary_fallback
• wear/src/main/java/com/example/wear/snippets/auth/OAuthDAG.kt:58, tag android_wear_auth_oauth_dag_authorize_device
• wear/src/main/java/com/example/wear/snippets/auth/OAuthPKCE.kt:47, tag android_wear_auth_oauth_pkce_create_request
• wear/src/main/java/com/example/wear/snippets/auth/OAuthPKCE.kt:74, tag android_wear_auth_oauth_pkce_send_request
• wear/src/main/java/com/example/wear/snippets/auth/WristDetectionUtility.kt:25, tag android_wear_auth_wrist_detection
• wear/src/main/java/com/example/wear/snippets/datalayer/DataLayerActivity.kt:128, tag android_wear_datalayer_auth_token_sharing
• wear/src/main/java/com/example/wear/snippets/datalayer/DataLayerService.kt:62, tag android_wear_datalayer_auth_token_sharing_listener

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[kul3r4]

One question for a tag where I can't see the corresponding END one