Add tests, check for gofmt, lint and docs

[umairidris]

We should add unit tests as well as integration tests for the provider.

[umairidris]

@xingao267 can you setup a cloud build trigger to make sure the provider at least builds on every release as a first step?

[xingao267]

Some additional checks to perform can include: lint, terraform validate and validate docs are generated properly by make docker_generate_docs command.