test: egress destination tests

[DanStough]

Changes proposed in this PR:

• Adds acceptance tests for the egress Destinations #1352
• Some refactoring to support extended usage of common functions in the t-gateway acceptance tests
• Adds a server that supports HTTPS, because right now we need an SNI or IP address to route the traffic. HTTP-only will be added before the 1.13 release.

How I've tested this PR:

• I've been running the acceptance test against a 3-node k3d cluster with some development images for Consul 1.13. All the necessary changes should be in the Consul 1.13 release branch.

How I expect reviewers to test this PR:

• Running the tests

Checklist:

• [X] Tests added
• [ ] ~CHANGELOG entry added~ (n/a)

[thisisnotashwin]

@DanStough Looks like the acceptance tests are failing for this test. Let me know if you would like to debug this together.

[DanStough]

@thisisnotashwin yeah I'm having some issues running the tests locally so I did a push-and-pray. I'm going to set up an x86 machine today so I can figure out what the issue is.

[thisisnotashwin]

@thisisnotashwin yeah I'm having some issues running the tests locally so I did a push-and-pray. I'm going to set up an x86 machine today so I can figure out what the issue is.

good luck and god speed 😛

[DanStough]

Sorry for the churn on this one, but we should be all good now for a review @thisisnotashwin @ishustava .

[david-yu]

@DanStough please merge when you're ready and able! Thanks again!