.env file not being used anymore

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## This issue is a:

- [ ] bug report
- [ ] request for new sample
- [ ] documentation issue or request
- [x] regression (a behavior that used to work and stopped in a new release)

## Further info:

On previous versions azure-sdk-for-go-samples used to rely on github.com/gobuffalo/envy to load variables from .env files. But that features has been dropped out.

All references to .env file as a way to setup environment variables should be dropped from the code

No files, tests, or entry points are named. Search the repository for .env and envy references, then remove references to .env-based setup and confirm that no such references remain.

Written by the indexing model from the issue text.