Use Environment Variables instead of CLI Arguments

[37ng]

Description

closes #11

• [x] Use envy and dotenvy to handle env var parsing.
• [x] Add tests

Side Notes

• Used dotenvy instead of dotenv due to Rustsec.

[codecov-commenter]

Codecov Report

All modified and coverable lines are covered by tests :white_check_mark:

:exclamation: No coverage uploaded for pull request base (insipx/resolveDid@80c3bca). Click here to learn what that means.

:exclamation: Your organization needs to install the Codecov GitHub app to enable full functionality.

Additional details and impacted files

```diff @@ Coverage Diff @@ ## insipx/resolveDid #18 +/- ## ==================================================== Coverage ? 89.36% ==================================================== Files ? 11 Lines ? 1185 Branches ? 0 ==================================================== Hits ? 1059 Misses ? 126 Partials ? 0 ```

:umbrella: View full report in Codecov by Sentry.
:loudspeaker: Have feedback on the report? Share it here.

[insipx]

first commit!!