E2E test suite

[devbugging]

Original PR: https://github.com/onflow/flow-cli/pull/635

Closes https://github.com/onflow/flow-cli/issues/330

Description This PR adds e2e testing of some of the basic commands used in the cli

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For contributor use:

• [ ] Targeted PR against master branch
• [ ] Linked to Github issue with discussion and accepted design OR link to spec that describes this work
• [ ] Code follows the standards mentioned here
• [ ] Updated relevant documentation
• [ ] Re-reviewed Files changed in the Github PR explorer
• [ ] Added appropriate labels