test: Allow integration tests to run against any accessible cheqd resolver

[jcourt562]

This is a very mechanical/repetitive, although large change to the integration test suite.

Problem Addressed:
The integration tests hardcode the host portion of all test Cheqd DID URLs to be localhost:8080. Whilst this works when running on a developers local machine and on GitHub it doesn't work for Gitlab pipelines which need a docker-in-docker container addressed as 'docker:8080'. Additionally with this set of changes it will be possible to run the integration tests against any publicly accessible/deployed cheqd resolver which could be useful in diagnosing field issues/anomalies.

Solution submitted
This change introduces an integration testing environment string variable called SUT_HOST_ADDRESS.
If the environment variable is set then the SUTHost test constant is set to that value in tests/constants/constants.go. If the environment variable is NOT set then the default behaviour is maintained with SUTHost being set to localhost:8080.
All current integration tests were changed to use SUTHost when creating DidURL using fmt.Sprintf() in place of the hardcoded localhost:8080

[lampkin-diet]

Thanks for your time and improvements! The overall look fine to me except variable name :)

[ankurdotb]

@lampkin-diet Can you please redirect this PR to a different branch that targets develop and just make the changes necessary? That way, our workflows will actually execute: it currently doesn't because it's coming from a fork.

1. Rename the variable to make it more obvious.
2. Can we make it default to localhost:8080, and if there's an environment variable provided, use the value provided by the environment variable? That way, there's always a valid value for this which should cover people who aren't specifically providing a value, and those who do can override the default.