compose: investigate moving set-redis-conn.bicep logic to upstream AVM

[JeffreyCA]

We currently rely on our own custom Bicep module set-redis-conn.bicep to write the Redis access key and connection strings to AKV after the cache has been provisioned.

We may want to move this logic upstream if possible, by having the Redis AVM support Secrets export, which would expose a standardized input param called secretsExportConfiguration.

We currently leverage this param for Cosmos DB:

azure-dev/cli/azd/resources/scaffold/templates/resources.bicept

Lines 94 to 97 in ccbf5e7

	secretsExportConfiguration: {
	keyVaultResourceId: keyVault.outputs.resourceId
	primaryWriteConnectionStringSecretName: 'MONGODB-URL'
	}

That way, as we add support for more services that involve access keys/secrets, they can all use the underlying AVM's secretsExportConfiguration to write to AKV.

Other Azure services whose AVM already support secrets export include:

• Cosmos DB
• Storage account
• SQL Server
• Cognitive services