Add CloudWatch config to HCP Log Streaming Destination

[leahrob]

Adding cloudwatch as a config option for the HCP Log Streaming Destination resource. IFACE-2483

🛠️ Description

🏗️ Acceptance tests

• Are there any feature flags that are required to use this functionality?
• Have you added an acceptance test for the functionality being added?
• Have you run the acceptance tests on this branch?

Output from acceptance testing:

TestAccHCPLogStreamingDestinationCloudwatch

$ make testacc TESTARGS='-run=TestAccHCPLogStreamingDestinationCloudwatch'
==> Checking that code complies with gofmt requirements...
golangci-lint run --config ./golangci-config.yml 
TF_ACC=1 go test ./internal/... -v -run=TestAccHCPLogStreamingDestinationCloudWatch -timeout 360m -parallel=10

=== RUN   TestAccHCPLogStreamingDestinationCloudWatch
--- PASS: TestAccHCPLogStreamingDestinationCloudWatch (6.36s)
PASS
ok      github.com/hashicorp/terraform-provider-hcp/internal/provider/logstreaming      7.483s

[manish-hashicorp]

Rubber stamping. Please get approval from your team before merging.