Added support for namespaces and adminPartitions

[Ganeshrockz]

This PR

• Adds -consul-namespace and -consul-admin-partition flags to the existing consul-aws command. This will enable Consul enterprise users to sync their AWS to custom namespaces and admin partitions and vice versa. The default value for both these fields is an empty string and so there should be no changes in experience for non enterprise use cases.
• Adds an integration test for the enterprise usecase.
• Fixes a bug which prevented properly syncing AWS services into Consul when -aws-prefix flag is non empty. Because of this bug, the existing integration test was a bit flaky
• Upgraded Go version of this repo to 1.20

[hanshasselberg]

LGTM, thanks for your work. My comments are no blockers, but I think it would be nice if Namespace and Partition are consistently (in CatalogDeregistration and CatalogRegistration or in AgentService) set only once across this PR.

[Ganeshrockz]

@hanshasselberg Thanks for the review. I removed the additional Partition field that is added to the CatalogRegistration request. Consul server throws the following error when creating a service

sync_test.go:60: error creating service in Consul: Unexpected response code: 500 (Cannot register services and checks for multiple partitions in one registration request)

I guess we should have adminPartition set in both the places. Thoughts?